MCQ 11 Mark
Electrophilic substitution reaction in phenol takes place at:
AnswerElectrophilic substitution reaction in phenol takes place at ortho and para position$. −OH$ is an ortho para directing group.
The electron density at ortho and para positions will be higher than the electron density at meta position.
View full question & answer→MCQ 21 Mark
Which reagent is suitable for this conversion?
AnswerCorrect option: B. $\mathrm{LiAlH}_4$
Suitable Reagent for this conversion is $\mathrm{LiAlH}_4$.
View full question & answer→MCQ 31 Mark
Methanol is now prepared from:
- A
- B
Sugar through fermentation
- C
- ✓
Both $A$ and $B$
AnswerCorrect option: D. Both $A$ and $B$
On an industrial scale, methanol is predominantly produced from natural gas by reforming the gas with steam and then converting and distilling the resulting synthesized gas mixture to create pure methanol. The result is a clear, liquid, organic chemical that is water$-$soluble and readily biodegradable.
Some methanol can be produced during fermentation, but this is not derived from the ethanol or by carbohydrate oxidation. It is produced in small amounts, either by non$-$enzymatic reactions or through the reduction of formaldehyde.
View full question & answer→MCQ 41 Mark
Mark the correct statement:
- ✓
Water gas is used in the manufacture of methyl alcohol.
- B
Water gas has the highest calorific value.
- C
Water gas burns with luminuous flame.
- D
The production of water gas is exothermic process.
AnswerCorrect option: A. Water gas is used in the manufacture of methyl alcohol.
View full question & answer→MCQ 51 Mark
Which of the following can not be the product of this reaction?
AnswerIn the mechanism of dehydration, after the removal of water, elimination of a Hydrogen atom only occurs from an $\alpha−$Carbon atom. Thus, it is quite evident that $(4)$ can not be the product of this reaction.
View full question & answer→MCQ 61 Mark
Acid catalysed hydration of alkenes except ethene leads to the formation of.
- A
- ✓
Secondary or tertiary alcohol.
- C
Mixture of primary and secondary alcohols.
- D
Mixture of secondary and tertiary alcohols.
AnswerCorrect option: B. Secondary or tertiary alcohol.
Alkenes react with water in the presence of acid as a catalyst to form alcohol. In case of unsymmetrical alkenes$, OH$ is added to the carbon having fewer hydrogen atoms according to Markovnikov's rule.
Hence, acid catalyzed hydration of alkenes except ethene leads to the formation of secondary or tertiary alcohol. To obtain primary alcohol, hydroboration oxidation is used.
View full question & answer→MCQ 71 Mark
$\text{IUPAC}$ name of the given compound is:
$\text{H}_3\text{C}\text{−CH}−\text{CH}_2\text{−CH}\text{−CH}−\text{CH}_2−\text{CH}_3\\ \ \ \ \ \ \ \ \ \ \ \ \ \ | \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ | \ \ \ \ \ \ \ \ | \\ \ \ \ \ \ \ \ \ \ \ \ \ \text{OH} \ \ \ \ \ \ \ \ \ \ \ \ \ \text{OH} \ \ \ \ \text{C}_2\text{O}_5$
- ✓
$5-$ethylheptane$-2.4-$diol
- B
$3-$ethylheptane$-4,6-$diol
- C
$4-$ethyl$-1-$methylhexane$-1,3-$diol
- D
AnswerCorrect option: A. $5-$ethylheptane$-2.4-$diol
The compound have ethyl group at carbon no $5,$ two hydroxyl groups at carbon no $2$ and $4.$ So its name is $5−$ethylheptane$−2.4−$diol.
View full question & answer→MCQ 81 Mark
The correct order of boiling point for primary $(1),$ secondary $(2)$ and tertiary $(3)$ alcohols is:
- ✓
$1 > 2 > 3$
- B
$3 > 2 > 1$
- C
$2 > 1 > 3$
- D
$2 > 3 > 1$
AnswerCorrect option: A. $1 > 2 > 3$
Alcohols with same molecular weight are expected to have almost same boiling point however two more factors other than molecular weight are important, they are namely $H-$bonding and surface area of molecule. Both these factors are least in $3$ alcohols and maximum in $1$ alcohols. Hence$, 3$ alcohols have least boiling point while $1$ alcohols have maximum boiling point.
View full question & answer→MCQ 91 Mark
Which of the following statement is not correct?
AnswerCorrect option: A. Phenol is neutralised by sodium carbonate.
Phenol does not react with $\mathrm{Na}_2 \mathrm{CO}_3$ because it is weaker acid than carboxylic acid and thereby do not have the strength to substitute or give away its $H^+$ ions to that of weak bases like sodium carbonate.
Phenol is used for the preparation of aspirin which is used as an analgesic as well as antipyretic drugs.
Phenol is more soluble in water than chlorobenzene due to formation of $H-$bond with water molecules.
$o-$nitrophenol form intramolecular $H−$bonding while $p-$nitrophenol form intermolecular $H−$bonding. Due to this, nature $o-$nitrophenol has a lower boiling point than $p-$nitrophenol.
View full question & answer→MCQ 101 Mark
The other name for Syngas is:
AnswerSyngas is also called as water gas which is a mixture of carbon monoxide and hydrogen.
View full question & answer→MCQ 111 Mark
How many alcohols with molecular formula $\mathrm{C}_4 \mathrm{H}_{10} \mathrm{O}$ are chiral in nature?
AnswerOnly one alcohol contains chiral carbon atom.
- $\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CH}_2 \mathrm{CH}_2 \mathrm{OH}$
- $\ \ \ \ \ \ \ \ \ \ \ \ \ \text{CH}_3 \\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ | \\ \text{CH}_3 - \text{C} - \text{OH} \\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ | \\ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{CH}_3$
- $\text{CH}_3\text{CH}_2\text{CH} - \text{CH}_3 \\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ | \\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{OH}$
Only $\text{III}$ is chiral in nature. View full question & answer→MCQ 121 Mark
The boiling point of methanol is greater than that of methyl thiol because:
- A
There is intramolecular hydrogen bonding in methanol and intermolecular hydrogen bonding in methyl thiol.
- ✓
There is intermolecular hydrogen bonding in methanol and no hydrogen bonding in methyl thiol.
- C
There is no hydrogen bonding in methanol and intermolecular hydrogen bonding in methyl thiol.
- D
There is no hydrogen bonding in methanol and intramolecular hydrogen bonding in methyl thiol.
AnswerCorrect option: B. There is intermolecular hydrogen bonding in methanol and no hydrogen bonding in methyl thiol.
Methanol has high boiling point than methyl thiol because there is intermolecular hydrogen bonding in methanol and no hydrogen bonding in methyl thiol.
View full question & answer→MCQ 131 Mark
In an aqueous solution at $25^{\circ} \mathrm{C}$ has twice as many $\mathrm{OH}^{-}$ as pure water its $\text{pOH}$ will be:
- ✓
$6.699$
- B
$7.307$
- C
$7$
- D
$6.98$
AnswerCorrect option: A. $6.699$
We know that pure water at $25^{\circ} \mathrm{C}$ has $10^{-7} \mathrm{M}$ of $\mathrm{OH}^{-}.$
According to the problem, the aqueous solution at the same temperature has $2 \times 10^{-7} \mathrm{M} \mathrm{OH}^{-}$
Therefore, its $\mathrm{pOH}=-\log \left(2 \times 10^{-7}\right)$
$\mathrm{pOH}=6.6989$
or, $\mathrm{pOH}=6.699$
View full question & answer→MCQ 141 Mark
View full question & answer→MCQ 151 Mark
Which of the following is most acidic?
AnswerCorrect option: D. $m-$Chlorophenol
Alcohols are less acidic than phenol. Further electron withdrawing group $($like $- Cl)$ increases the acidity of phenol, therefore$, m-$chlorophenol is most.
View full question & answer→MCQ 161 Mark
Give $\text{IUPAC}$ name of the compound given below.$\text{CH}_3-\text{CH}-\text{CH}_2-\text{CH}_2-\text{CH}-\text{CH}_3 \\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ | \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ | \\ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{Cl} \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{CH}$
AnswerCorrect option: C. $5-$Chlorohexan$-2-$ol.
Priority will be given to $-OH$ group.
View full question & answer→MCQ 171 Mark
The $\text{IUPAC}$ name of the following compound is:
- ✓
$3-$cyclohexylpentan$-3-$ol
- B
$3-$cyclohexyl$,3-$hydroxypentane
- C
$3-$hydroxypentyl cyclohexane
- D
AnswerCorrect option: A. $3-$cyclohexylpentan$-3-$ol
The $\text{IUPAC}$ name of the given compound is $3-$Cyclohexylpentan$-3-$ol.
The parent compound contains $5 C$ atoms and is named pentane.
A hydroxyl group is present at third $C$ atom.
Hence, the last alphabet $e$ of pentane is replaced with the suffix $-3-$ol.
A cyclohexyl ring is present as substituent at third carbon atom.
View full question & answer→MCQ 181 Mark
Phenol is less acidic than $.......$
- A
- ✓
$o-$nitrophenol.
- C
$o-$methylphenol.
- D
$o-$methoxyphenol.
AnswerCorrect option: B. $o-$nitrophenol.
In substituted phenols, the presence of electron withdrawing group such as nitro group, enhances the acidic strength of phenol. This effect is more pronounced when such a group is present at ortho and para positions. It is due to the effective delocalisation of negative charge in phenoxide ion. On the other hand, electron releasing groups, such as alkyl groups, in general, do not favour the formation of phenoxide ion resulting in decrease in acid strength. Cresols, for example, are less acidic than phenol.
View full question & answer→MCQ 191 Mark
During dehydration of alcohols to alkenes by heating with conc$. \mathrm{H}_2 \mathrm{SO}_4$, the initiation step is:
- A
- B
- C
Formation of carbocation.
- ✓
Protonation of alcohol molecule.
AnswerCorrect option: D. Protonation of alcohol molecule.
Dehydration of alcohol to alkene in presence of concentrated $\mathrm{H}_2 \mathrm{SO}_4$ involves following steps:
Thus, the initiation step is protonation of alcohol.
View full question & answer→MCQ 201 Mark
Which of the following cannot be dissolved in alcohol?
AnswerRubber and plastic cannot be dissloved in alchol because of nonpolar nature of rubber and plastics.
View full question & answer→MCQ 211 Mark
Which of the following is soluble in water?
AnswerCorrect option: B. $\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}$
Ethanol $\left(\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}\right)$ forms hydrogen bonding with water.
Hence, it is soluble in water.
View full question & answer→MCQ 221 Mark
Which of the following alcohol does not give a stable compound on dehydration?
- A
- ✓
- C
$n-$propyl alcohol
- D
$n-$butyl alcohol
AnswerAlcohols undergo dehydration $($removal of water$)$ to form an alkene.
To form alkene, we need at least two carbon atoms. But, methanol $(\mathrm{CH}_3 \mathrm{OH})$ has only one carbon atom. So, it does not give a stable compound on dehydration.
View full question & answer→MCQ 231 Mark
Which of the following substance will increase the acidity of phenol?
- ✓
Dil$. \mathrm{H}_2 \mathrm{SO}_4$
- B
Dil$. \text{HCl}$
- C
Conc$. \mathrm{H}_2 \mathrm{SO}_4$
- D
Conc$. \mathrm{CH}_3 \mathrm{COOH}$
AnswerCorrect option: A. Dil$. \mathrm{H}_2 \mathrm{SO}_4$
Dilute $\mathrm{H}_2 \mathrm{SO}_4$ will increase the acidity of phenol. This is because now phenol will be easily able to donate $\mathrm{H}^{+}$ ion and delocalise its negative charge more efficiently. Also addition of dilute $\mathrm{H}_2 \mathrm{SO}_4$ which is itself an acid increases the acidity of phenol.
View full question & answer→MCQ 241 Mark
Among the three isomers of the nitrophenol, the one that is least soluble in water is:
- A
$m-$nitrophenol
- ✓
$o-$nitrophenol
- C
$p-$nitrophenol
- D
AnswerCorrect option: B. $o-$nitrophenol
Intramolecular hydrogen bonding in ortho$-$substituted nitrophenol reduces water solubility and increases volatility.
Thus$, o-$nitrophenol is steam distillable while the isomeric $p-$nitrophenol is soluble in water.
View full question & answer→MCQ 251 Mark
What type of spectroscopy would be the best tool to analyze a clear and colorless solution for the presence of a functional group like an alcohol group $(−OH)?$
- A
$UV$ spectroscopy.
- ✓
$IR$ spectroscopy.
- C
- D
Photoelectron spectroscopy.
AnswerCorrect option: B. $IR$ spectroscopy.
Functional groups are best analyzed by $IR$ spectroscopy$. IR$ is infrared spectroscopy that works in $IR$ region of electromagnetic radiations. stretching frequencies of functional groups are measured due to their vibration around bonds. Every functional groups have their particular stretching frequency range.In this way functional groups are analyzed by $IR.$
View full question & answer→MCQ 261 Mark
$3-$methyl$-2-$pentene on reaction with $\text{HOCl}$ gives:
- A
$3-$chloro$-3-$methyl pentanol$-2$
- B
$2,3-$dichloro$-3-$methyl pentane
- ✓
$2-$chloro$-3-$methyl pentanol$-3$
- D
$2,3$ dimethyl butanol$-2$
AnswerCorrect option: C. $2-$chloro$-3-$methyl pentanol$-3$
The given reaction follows Markownikoff's addition mechanism and add $\mathrm{OH}^{-}$and $\mathrm{Cl}^{+}$ across carbon$-$carbon double bond.
View full question & answer→MCQ 271 Mark
Write the $\text{IUPAC}$ name of the given compound:$\text{HO}−\text{CH}_2−\text{CH}−\text{CH}_2−\text{OH}\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ ∣ \\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{CH}_3$
- ✓
$2-$Methylpropane$-1,3-$diol
- B
$2-$Methylpropan-$1,3-$dial
- C
$1-$Hydroxy$-2-$methylpropan$-1-$ol
- D
AnswerCorrect option: A. $2-$Methylpropane$-1,3-$diol
The given compound can be numbered from left to right or vice versa. At the $2^{nd}$ position, there is a methyl group and is designated as $2-$Methyl.
The parent carbon chain contains $3$ carbon atoms resembling propane and at the positions $1$ and $3,$ there's the hydroxyl group designated as $1, 3-$diol.
So the $\text{IUPAC}$ name of the given compound is $2-$Methylpropane$-1, 3-$diol.
View full question & answer→MCQ 281 Mark
Correct order of acidic strength.
- A
$\text{I>II>III}$
- ✓
$\text{II>III>I}$
- C
$\text{I>III>II}$
- D
$\text{III>II>I}$
AnswerCorrect option: B. $\text{II>III>I}$
Acidic nature $\alpha−I$
View full question & answer→MCQ 291 Mark
Ethers show dipolar nature due to the presence of $........$
- A
Central $C$ atom
- ✓
Central $O$ atom
- C
Central $N$ atom
- D
AnswerCorrect option: B. Central $O$ atom
Ethers have general structural formula $R-O-R\ '.$ Hence all of them have the $C-O$ bond. We know that the $C-O$ bond is polar due to the difference between the electronegativities of carbon and oxygen. Hence, ethers show dipolar nature.
View full question & answer→MCQ 301 Mark
The $\text{IUPAC}$ name of sec. butyl alcohol is:
- A
$1-$butanol
- ✓
$2-$butanol
- C
$2-$methyl$-l-$butanol
- D
$2-$methyl$-2-$butanol
AnswerCorrect option: B. $2-$butanol
The $\text{IUPAC}$ name of the sec. butyl acohol is $2-$butanol because the longest continue chain contain $4-$carbon as well as the $−OH$ group is attached to $2^{nd}$ carbon , hence the name is $2-$butanol.
View full question & answer→MCQ 311 Mark
Arrange the following alkanols $1, 2$ and $3$ in order of their reactivity towards acid catalyzed dehydration.
- A
$1>2>3$
- B
$2>1>3$
- ✓
$2>3>1$
- D
$3>2>1$
AnswerCorrect option: C. $2>3>1$
View full question & answer→MCQ 321 Mark
Dehydration of alcohol is an example of which type of reaction?
AnswerWhen heated with strong acids catalysts, alcohols typically undergo a $1,2-$elimination reactions to generate an alkene and water. Also known as dehydration since it involves the removal of a molecule of water.
View full question & answer→MCQ 331 Mark
Which of the following order is true regarding the acidic nature of phenol?
- A
Phenol $> O -$cresol $> O-$nitrophenol
- B
Phenol $> O -$nitrophenol $> O-$cresol
- ✓
$O-$cresol $<$ phenol $< O-$ nitrophenol
- D
Phenol $< O-$cresol $< O-$nitrophenol
AnswerCorrect option: C. $O-$cresol $<$ phenol $< O-$ nitrophenol
The following order is true regarding the acidic nature of phenol.
$O-$cresol $<$ phenol $< O-$ nitrophenol.
Phenols having electron withdrawing substituents such as nitro group are more acidic due to delocalization of negative charge.
Phenols having electron releasing substituents such as alkyl group are less acidic as negative charge is not delocalised.
View full question & answer→MCQ 341 Mark
The order of reactivity of the following alcohols towards dehydration is:
- A
$\text{IV>I>II>III}$
- B
$\text{III>IV>II>I}$
- ✓
$\text{II>I>III>IV}$
- D
$\text{II>III>I>IV}$
AnswerCorrect option: C. $\text{II>I>III>IV}$
Reactivity of alcohol towards dehydration is increased by the stability of the carbocation formed subsequently. Order of carbocation stability is:
tertiary$>$secondary$>$primary.
Also presence of $+I$ groups like $CH_3$ increases the stability.
According to this the order of reactivity is$, \text{II>I>III>IV}$
View full question & answer→MCQ 351 Mark
Which of the following compounds will react with sodium hydroxide solution in water?
- ✓
$ \mathrm{C}_6 \mathrm{H}_5 \mathrm{OH} . $
- B
$ \mathrm{C}_6 \mathrm{H}_5 \mathrm{CH}_2 \mathrm{OH} . $
- C
$ \left(\mathrm{CH}_3\right)_3 \mathrm{COH} . $
- D
$ \mathrm{C}_2 \mathrm{H}_5 \mathrm{OH} $
AnswerCorrect option: A. $ \mathrm{C}_6 \mathrm{H}_5 \mathrm{OH} . $
Phenol being more acidic reacts with sodium hydroxide solution in water to give sodium phenoxide which is resonance stabilized.
Alcohols are very weak acids.
$\mathrm{C}_6 \mathrm{H}_5 \mathrm{OH}+\mathrm{NaOH} \rightarrow \mathrm{C}_6 \mathrm{H}_5 \mathrm{ONa}+\mathrm{H}_2 \mathrm{O}$
View full question & answer→MCQ 361 Mark
Monochlorination of toluene in sunlight followed by hydrolysis with aq$. \text{NaOH}$ yields.
- A
$o-$Cresol.
- B
$m-$Cresol.
- C
$2, 4-$Dihydroxytoluene.
- ✓
AnswerMonochlorination of toluene in sunlight gives benzyl chloride. On hydrolysis with aq$. \text{NaOH},$ benzyl chloride, shows nucleophilic substitution reaction to give benzyl alcohol.
View full question & answer→MCQ 371 Mark
The major product obtained on acid $-$ catalysed hydration of $2-$phenylpropene is:
- ✓
$2-$phenylpropan$-2-ol$
- B
$2-$phenylpropan$-1-01$
- C
$3-$phenylpropan$-2-ol$
- D
$1-$phenylpropan$-1-ol$
AnswerCorrect option: A. $2-$phenylpropan$-2-ol$
The major product obtained on acid $-$ catalysed hydration of $2-$phenylpropene is $2-$Phenylpropan$-2-ol.$ A molecule of water is added to $C=C$ double bond$. −OH$ group is added to more substituted $C$ atom.
View full question & answer→MCQ 381 Mark
Which of the following combinations can be used for the preparation of cis vic diol?
AnswerCorrect option: B. Alkene $,\ce{OsO_4}$
Osmium tetroxide $(\ce{OsO_4})$ is a volatile liquid that is most useful for the synthesis of $1,2$ diols from alkene.
The $\ce{OsO_4}$ is a catalyst. It reacts with the π electrons of the alkene in a syn addition to form a cyclic osmate ester.
The $OH⁻$ hydrolyzes the ester. This forms the cis-diol and $\ce{H_4OsO_4}$.
View full question & answer→MCQ 391 Mark
The common name for propan$-2-ol$ is:
- A
$n-$Propyl alcohol.
- ✓
iso$-$Propyl alcohol.
- C
- D
AnswerCorrect option: B. iso$-$Propyl alcohol.
Isopropyl alcohol $(\text{IUPAC}$ name $2-$propanol$),$ also called isopropanol or dimethyl carbinol.
View full question & answer→MCQ 401 Mark
What is the $\text{IUPAC}$ name of the following compound$?\ \ce{CH_3−CH_2−CH_2−OH}$
- ✓
Propan$-1-ol$
- B
Propan$-2-ol$
- C
Propane$-1-ol$
- D
Ethane$-2-ol$
AnswerCorrect option: A. Propan$-1-ol$
In this compound, the number of carbon atoms is $3.$ So, the parent alkane is propane.
The functional group present is $−OH$ i.e alcohol$. −OH$ is present at the first carbon atom.
Thus the $\text{IUPAC}$ name is Propan $- 1 - ol.$
View full question & answer→MCQ 411 Mark
Which of the following species show maximum volatility?
- A
$\ce{CH_3CH_2OH}$
- ✓
$\ce{CH_3−O−CH_3}$
- C
$\ce{H_2O}$
- D
$HF$
AnswerCorrect option: B. $\ce{CH_3−O−CH_3}$
Due to the lack of any Hydrogen bonding in case of $\ce{CH_3−O−CH_3},$ its boiling point is comparatively low. In other words, it is the most volatile among the given compounds.
View full question & answer→MCQ 421 Mark
$\ce{CH_3CH_2OH}$ can be converted into $\ce{CH_3CHO}$ by $........$
AnswerCorrect option: C. Treatment with pyridinium chlorochromate.
Alcohols are oxidized to aldehydes and finally to acids.
$\text{CH}_3\text{CH}_2\text{OH}\xrightarrow{[\text{O}]}\text{CH}_3\text{CHO}\xrightarrow{[\text{O}]}\text{CH}_3\text{COOH}$
Oxidations can be stopped at aldehyde stage by using puridinium chlorochromate $(\ce{CrO_3C_5H_5N.HCl})$
$\text{CH}_3\text{CH}_2\text{OH}\xrightarrow{\text{PCC}}\text{CH}_3\text{CHO}$
View full question & answer→MCQ 431 Mark
The miscibility of ether with $......$ resembles those of alcohol of the same molecular mass.
AnswerThe miscibility of ether with water resembles those of alcohol of the same moleculer mass. It is generally due to the hydrogen bonding with water in alcohol.
View full question & answer→MCQ 441 Mark
Ethene reacts with $Y$ to produce ethanol. ethene $+ Y \rightarrow $ ethanol What is $Y\ ?$
AnswerEthanol can be manufactured by hydration of ethene.
Ethene is heated with steam in the presence of a catalyst of phosphoric acid to produce ethanol.
$\mathrm{C}_2 \mathrm{H}_4+\mathrm{H}_2 \mathrm{O} \rightarrow \mathrm{C}_2 \mathrm{H}_5-\mathrm{OH}$
View full question & answer→MCQ 451 Mark
Formation of $2-$butene as a major product by dehydration of $2-$butanol is according to:
- A
- ✓
- C
- D
Anti$-$markownikoff rule
AnswerThe formation of $2-$butene as major product by dehydration of $2-$butanol is according to Saytzeff rule.
The minor product is $1-$butene.
In this reaction, more substituted alkene is obtained as it is more stable.
View full question & answer→MCQ 461 Mark
Which of the following are used to convert $\text{RCHO}$ into $\ce{RCH_2OH}\ ?$
$a. H_2/Pd.$
$b. \ce{LiAlH_4}.$
$c. \ce{NaBH_4}.$
$d.$ Reaction with $\text{RMgX}$ followed by hydrolysis.
- ✓
$a,b$ and $c$
- B
$a ,b,c$ and $d$
- C
$b, c$ and $d$
- D
$a,c$ and $d$
AnswerCorrect option: A. $a,b$ and $c$
Aldehydes and ketones are reduced to the corresponding alcohols by addition of hydrogen in the presence of catalysts $($catalytic hydrogenation$).$ It is also prepared by treating aldehydes and ketones with sodium borohydride $(\ce{NaBH_4})$ or lithium aluminium hydride $(\ce{LiAlH_4}).$
View full question & answer→MCQ 471 Mark
Salicylic acid, picric acid, aspirin, nylon and plastics have a common raw material, namely:
AnswerPhenol is used as starting material in the manufacture of nylon, plastics, aspirin, picric acid, and salicylic acid, etc.
View full question & answer→MCQ 481 Mark
What is the hybridisation of carbon and oxygen in electronic structure of ether?
- A
$sp^3$ and $sp^2$
- ✓
$sp^3$ and $sp^3$
- C
$sp$ and $sp$
- D
$sp^2$ and $sp^2$
AnswerCorrect option: B. $sp^3$ and $sp^3$
$sp^3 (4-$bond pairs$)$ and $sp^3(2-$bond pairs and $2-$lone pairs$)$ hybridisations of carbon and oxygen in the electronic structure of an ether.
View full question & answer→MCQ 491 Mark
The process of converting alkyl halides into alcohols involves $.......$
- A
- ✓
- C
Dehydrohalogenation reaction.
- D
AnswerThe reaction is a type of nucleophilic substitution reaction in which $-Cl$ group is replaced by $-OH.$
View full question & answer→MCQ 501 Mark
The decreasing order of boiling points of the following alcohols is?
- A
$3-$methylbutan$-2-ol > 2-$methylbutan$-2-ol >$ pentan$-1-ol.$
- ✓
pentan$-1-ol > 3-$methylbutan$-2-ol > 2-$methylbutan$-2-ol.$
- C
$2-$methylbutan$-2-ol > 3-$methylbutan$-2-ol >$ pentan$-1-ol.$
- D
$2-$methylbutan$-2-ol >$ pentan$-1-ol >3-$methylbutan$-2-ol.$
AnswerCorrect option: B. pentan$-1-ol > 3-$methylbutan$-2-ol > 2-$methylbutan$-2-ol.$
$3-$methylbutan$-2-ol$ is a secondary alcohol
$\mathrm{CH}_3 \mathrm{CH}\left(\mathrm{CH}_3\right) \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_3$
$2-$methylbutan$-2-ol$ is a tertiary alcohol
$\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{C}\left(\mathrm{CH}_3\right)(\mathrm{OH}) \mathrm{CH}_3$
pentan$-1-ol$ is a primary alcohol
$\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CH}_2 \mathrm{CH}_2 \mathrm{CH}_2 \mathrm{OH}$
Boiling point of alcohols is determined by the ease and extent of $H-$bonding among the alcohol molecules. Tertiary alcohols being highly hindered will have least hydrogen bonding and thus low boiling point as compared to less hindered secondary alcohol.
Therefore the order of boiling point is primary alcohol$>$secondary alcohol$>$tertiary alcohol as:
pentan$-1-ol > 3-$methylbutan$-2-ol > 2-$methylbutan$-2-ol.$
View full question & answer→MCQ 511 Mark
Which of the following compounds is aromatic alcohol?
- A
$\text{A, B, C, D}.$
- B
$A, D.$
- ✓
$B, C.$
- D
$A.$
AnswerCorrect option: C. $B, C.$
Compound $(A)$ i.e., phenol and compound $(D)$ i.e., a derivative of phenol cannot be considered as aromatic alcohol. As phenol is also known as, carbolic acid cannot be considered as aromatic alcohol.
Compound $(B)$ and $(C), -OH$ group is bonded to $sp^3$ hybridised carbon which in turn is bonded to benzene ring.
View full question & answer→MCQ 521 Mark
Which of the following is produced during the following reaction$?\ \text{CO(g)} + \text{H}_2\text{(g)}\xrightarrow[\text{ZnO}\text{Cr}_2\text{O}_3]{575\text{k}}$
AnswerMethanol is produced during the following reaction
$\text{CO(g)} + \text{H}_2\text{(g)}\xrightarrow[\text{ZnO}\text{Cr}_2\text{O}_3]{575\text{k}}\text{CH}_3\text{OH}$
A mixture of $CO$ and hydrogen $(1:2$ molar ratio$)$ is called synthetic gas.
It is heated to a temperature of $573K$ in presence of $\ce{ZnO/Cr_2O_3}$ catalyst to form methanol.
It is industrial method of preparation of methanol.
View full question & answer→MCQ 531 Mark
The $\text{IUPAC}$ name of the following compound is:
- ✓
$1-$Phenylpropan$-2-ol$
- B
$3-$Phenylpropan$-2-ol$
- C
$2-$Hydroxypropylbenzene
- D
AnswerCorrect option: A. $1-$Phenylpropan$-2-ol$
The $\text{IUPAC}$ name of the given compound is $1-$Phenylpropan$-2-ol.$
The parent hydrocarbon contains $3 C$ atoms and is named as propane.
A hydroxyl group $(−OH)$ is present at second $C$ atom.
Hence, the last alphabet e of propane is replaced with the suffix $-2-ol.$
A phenyl group is present as a substituent at first carbon atom.
View full question & answer→MCQ 541 Mark
Common name for methanol is:
AnswerMethanol acquired the name "wood spirit" because it was once produced chiefly as a byproduct of the destructive distillation of wood.
View full question & answer→MCQ 551 Mark
The $\text{IUPAC}$ name of $\mathrm{CH}_3-\mathrm{C}\left(\mathrm{CH}_3\right)(\mathrm{OH}) \mathrm{CH}_2-\mathrm{CH}\left(\mathrm{CH}_3\right)_2$ is:
- ✓
$2,4-$Dimethylpentan$-2-ol$
- B
$2,4-$dimethylpentan$-4-ol$
- C
$2,2-$dimethylbutane
- D
$2,4,4-$trimethylbutan$-2-ol$
AnswerCorrect option: A. $2,4-$Dimethylpentan$-2-ol$
In the longest carbon chain,$ −OH$ group is closest to the left$-$hand side, therefore we number from the left-hand side.
There is $5$ carbon in the longest chain, in second and fourth positions methyl group is attached and in second position there is an alcoholic group. Thus $\text{IUPAC}$ name is $2,4-$Dimethyl pentan$-2-ol.$
View full question & answer→MCQ 561 Mark
The compound which gets dissolved in water is:
- A
$\mathrm{C}_2 \mathrm{H}_6$
- B
$\mathrm{C}_2 \mathrm{H}_4$
- C
$\mathrm{C}_2 \mathrm{H}_2$
- ✓
$\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}$
AnswerCorrect option: D. $\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}$
Ethanol has electronegative oxygen atom in it, and hence it takes part in hydrogen bonding with water.
Because of excessive hydrogen bonding with water, Ethanol dissolves in it.
View full question & answer→MCQ 571 Mark
Which of the following alkenes on acid$-$catalysed hydration gives a tertiary alcohol:
- A
$2−$Butene
- B
- C
- ✓
$\alpha−$Butylene
AnswerCorrect option: D. $\alpha−$Butylene
View full question & answer→MCQ 581 Mark
Among ethanol, dimethyl ether, methanol and propanal, the isomers are:
- A
Ethanol, dimethyl ether, methanol and propanal
- B
- C
Ethanol, dimethyl ether, and methanol
- ✓
Ethanol and dimethyl ether
AnswerCorrect option: D. Ethanol and dimethyl ether
Ethanol $\left(\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}\right)$ and dimethyl ether $\left(\mathrm{CH}_3-\mathrm{O}-\mathrm{CH}_3\right)$ have same molecular formula but different functional groups, so they are isomers.
View full question & answer→MCQ 591 Mark
An ester can be prepared by the reaction of:
- A
- B
An alcohol and an aldehyde.
- ✓
An alcohol and an organic acid.
- D
AnswerCorrect option: C. An alcohol and an organic acid.
Esters $(\text{RCOOR}\ ')$ are prepared by the reaction between alcohol $(\ce{R\ 'OH})$ and organic acid $(\text{RCOOH}).$
View full question & answer→MCQ 601 Mark
Unlike phenol,$ 2,4-$dinitrophenol is soluble in sodium carbonate solution in water because?
- ✓
Presence of two $-\mathrm{NO}_2$ groups in the ring makes $2, 4 -$ dinitrophenol a stronger acid than phenol.
- B
Presence of two $-\mathrm{NO}_2$ groups in the ring makes $2, 4 -$ dinitrophenol a weaker acid than phenol.
- C
presence of two $-\mathrm{NO}_2$ groups make the hydrogen bonding easier, making $2, 4-$dinitrophenol soluble.
- D
Nitro group reacts with $\mathrm{Na}_2 \mathrm{CO}_3$ while $-OH$ group does not.
AnswerCorrect option: A. Presence of two $-\mathrm{NO}_2$ groups in the ring makes $2, 4 -$ dinitrophenol a stronger acid than phenol.
Presence of two electron withdrawing $-\mathrm{NO}_2$ groups in the ring makes $2,4-$dinitrophenol a stronger acid than phenol. Hence it react with aqueous $\mathrm{Na}_2 \mathrm{CO}_3$ solution to form sodium salt thus making it soluble in $\mathrm{Na}_2 \mathrm{CO}_3$.
View full question & answer→MCQ 611 Mark
Ethanol on reaction with acetic anhydride gives:
- A
- B
- C
- ✓
Ethyl acetate and ethanoic acid
AnswerCorrect option: D. Ethyl acetate and ethanoic acid
The reaction of acetic anhydride with ethanol yields ethyl acetate and ethanoic acid.
$\left(\mathrm{CH}_3 \mathrm{CO}_2\right)_2 \mathrm{O}+\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{OH} \rightarrow \mathrm{CH}_3 \mathrm{COOCH}_2 \mathrm{CH}_3+\mathrm{CH}_3 \mathrm{COOH}$
View full question & answer→MCQ 621 Mark
Molecular formula of ethanol is?
- A
$\mathrm{CH}_3 \mathrm{OH}$
- B
$\mathrm{C}_2 \mathrm{H}_4(\mathrm{OH})_2$
- ✓
$\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}$
- D
$\text{HCHO}$
AnswerCorrect option: C. $\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}$
Ethanol is alcohol and is a primary $1$ degree monohydric alcohol with moleculer formula $\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}$.
View full question & answer→MCQ 631 Mark
Phenol reacts with bromine water in carbon disulphate at low temperature to give:
AnswerCorrect option: B. $o-$ and $p-$bromophenols
$−OH$ is ring activating group because it is electron$-$donating so it is ortho and para director with compound $o-$ and $p-$bromophenols.
View full question & answer→MCQ 641 Mark
Primary, secondary and tertiary alcohols can be distinguish by:
AnswerPrimary alcohols react on heating with Lucas elegant.
Secondary alcohols react with Lucas reagent after $5$ min tertiary alcohol react immediately with Lucas reagent.
View full question & answer→MCQ 651 Mark
Which is the best reagent to convert cyclohexanol into cyclohexene?
AnswerCorrect option: C. Conc. $\mathrm{H}_3 \mathrm{PO}_4$
Cyclohexanol is used as substrate and phosphoric acid is present as catalyst which promotes the reaction but is not consumed in it. The hydroxyl group in $\ce{R-OH}$ is a poor leaving group because it leaves as hydroxide ion. An acid is used to protonate the alcohol and form $\text{R}−\text{OH}_2^+$
View full question & answer→MCQ 661 Mark
Ethyl alcohol exhibits acidic character on reacting with:
- A
- ✓
- C
- D
Acidic potassium dichromate.
Answer$\mathrm{CH}_3 \mathrm{CH}_2-\mathrm{OH}+\mathrm{Na} \rightarrow \mathrm{CH}_3-\mathrm{CH}_2-\mathrm{O}^{-} \mathrm{Na}^{+}+ \frac {1}{2}\mathrm{\sim H}_2$
Acid reacts with metal to give hydrogen gas.
Hence, in above reaction $\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{OH}$ behaves as an acid.
View full question & answer→MCQ 671 Mark
Lower alcohols are highly soluble in water due to $.......$
- A
Van der Waal's attraction
- B
Dipole dipole interaction
- C
- ✓
$H-$bonding
AnswerCorrect option: D. $H-$bonding
The solubility of lower alcohols is due to the existence of hydrogen bonds between water and polar $-OH$ group of alcohol molecules.
The $-OH$ group in alcohols and phenols contain a hydrogen bonded to an electronegative oxygen atom. Thus they form hydrogen bonds with water molecules.
View full question & answer→MCQ 681 Mark
Which of the following is the functional group of an ether?
- A
$\text{R−OH}$
- ✓
$\text{R−O−R}$
- C
$\text{R−CO−R}\ ′$
- D
$\text{R−COOH}$
AnswerCorrect option: B. $\text{R−O−R}$
$\text{R−O−R}$ is generally the functional group of the ether which is non$-$polar and does not form hydrogen bonding.
View full question & answer→MCQ 691 Mark
Methanol can be prepared when:
- ✓
Iodomethane is heated with moist silver oxide.
- B
Iodomethane react with sodium in the presence of ether.
- C
Both $A$ and $B.$
- D
AnswerCorrect option: A. Iodomethane is heated with moist silver oxide.
Moist Silver oxide
$\mathrm{Ag}_2 \mathrm{O}+\mathrm{H}_2 \mathrm{O} \rightarrow 2 \mathrm{AgOH}$
$\mathrm{CH}_3-\mathrm{I}+\mathrm{AgOH} \rightarrow \mathrm{CH}_3-\mathrm{OH}+\mathrm{AgI}$
Therefore, methanol can be prepared when iodomethane is heated with moist silver oxide.
View full question & answer→MCQ 701 Mark
Which of the following alcohol has the highest boiling point?
- A
Butan$−2−ol$
- ✓
$2−$Methylpropan$−2−ol$
- C
Propan$−2−ol$
- D
Butan$−1−ol$
AnswerCorrect option: B. $2−$Methylpropan$−2−ol$
Creakr the molecules mass, higher the boiling point, further greather the branching, lesser the boiling. Point.
View full question & answer→MCQ 711 Mark
Which of the following reactions is possible?
- A
$\ce{Me_3C−ONa + Me_3C−Br \rightarrow Me_3C−O−CMe_3}$
- B
$\ce{Me_2CH−ONa + Me_2 + Me_2CHMe_2CHBr \rightarrow Me_2CH−O−CHMe_2}$
- C
$\ce{PhONa + PhBr \rightarrow PhOPh}$
- ✓
$\ce{PhONa + CH_3Br \rightarrow PhOCH_3}$
AnswerCorrect option: D. $\ce{PhONa + CH_3Br \rightarrow PhOCH_3}$
Six types of ethers cannot be prepared by Williamson's synthesis.
Not feasible, $\ce{RX = 3^\circ , RONa} = 3^\circ $
Not feasible, $\ce{RX = 2^\circ , RONa} = 2^\circ $
Not feasible, $\ce{ArX,}$
Feasible, $\ce{RX = 1^\circ , ArONa}$
View full question & answer→MCQ 721 Mark
Consider the reaction between $\mathrm{C}_2 \mathrm{H}_5 \mathrm{O}^{\ominus}$ and dimethyl sulphate. The leaving group in this reaction is:
AnswerCorrect option: A. $\mathrm{MeOSO}_2 \mathrm{O}^{\ominus}$
View full question & answer→MCQ 731 Mark
An example for a polyhydric alcohol is:
AnswerSo, mannitol is a polyhydric alcohol, because it has $6-OH$ groups. Rest all are monohydric alcohols because they contain single hydroxy group.
View full question & answer→MCQ 741 Mark
Mixed ether will not be formed in the reaction?
- A
$ \mathrm{CH}_3 \mathrm{OCH}_2 \mathrm{Cl}+\mathrm{C}_2 \mathrm{H}_5 \mathrm{MgBr} $
- B
$ \mathrm{CH}_2 \mathrm{~N}_2+\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH} $
- C
$ \mathrm{C}_2 \mathrm{H}_5 \mathrm{ONa}+\mathrm{CH}_3 \mathrm{I} $
- ✓
$ \mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}+\mathrm{H}_2 \mathrm{SO}_4\left(140^{\circ} \mathrm{C}\right) $
AnswerCorrect option: D. $ \mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}+\mathrm{H}_2 \mathrm{SO}_4\left(140^{\circ} \mathrm{C}\right) $
$\mathrm{C}_2 \mathrm{H}_5-\mathrm{OH}+\mathrm{H}_2 \mathrm{SO}_4\left(140^{\circ} \mathrm{C}\right) \rightarrow \mathrm{C}_2 \mathrm{H}_5-\mathrm{O}-\mathrm{C}_2 \mathrm{H} 5+\mathrm{H}_2 \mathrm{O}$
Ethyl alcohol when heated with Sulphuric acid at $140^\circ C$ produces a symmetric ether i.e. Diethyl ether.
View full question & answer→MCQ 751 Mark
$\ \ \ \ \ \ \ \ \ \text{CH}_3\\\ \ \ \ \ \ \ \ \ \ \ \ |\\\text{CH}_3−\text{C}−\text{CH}_2−\text{CH}_3\\\ \ \ \ \ \ \ \ \ \ \ \ |\\\ \ \ \ \ \ \ \ \ \ \text{OH}$
The correct $\text{IUPAC}$ name of the above compound is:
AnswerCorrect option: B. $2-$methylbutan$-2-ol$
The $\text{IUPAC}$ name of the given compound is $2-$Methylbutan$-2-ol.$
The parent hydrocarbon contains $4$ carbon atoms and is named butane.
A methyl substituent is present at second $C$ atom.
A hydroxyl group is present at second $C$ atom.
Hence, the last alphabet e of butane is replaced with the suffix$ -2-ol.$
View full question & answer→MCQ 761 Mark
Carbinol is a trivial name of:
- A
$\ce{C_2H_5OH}$
- ✓
$\ce{CH_3OH}$
- C
$\text{HCOOH}$
- D
$\ce{CH_3COOH}$
AnswerCorrect option: B. $\ce{CH_3OH}$
Carbinol is a trivial name of methanol $\ce{CH_3OH}.$
View full question & answer→MCQ 771 Mark
Reagents used for industrial preparation of methanol are:
- ✓
$\ce{CO + H_2}$
- B
$\ce{HCHO + H_2}$
- C
$\ce{CO_2 + H_2}$
- D
$\ce{HCOOH + H_2}$
AnswerCorrect option: A. $\ce{CO + H_2}$
Carbon monoxide and hydrogen react over a catalyst to produce methanol. Today, the most widely used catalyst is a mixture of copper and zinc oxides,supported on alumina.At $\ce{5–10\ MPa (50–100 atm)}$ and $250^\circ C (482^\circ F),$ the reaction is characterized by high selectivity $(>99.8\%).$
$\ce{CO + 2H_2 \longrightarrow CH_3OH}$
View full question & answer→MCQ 781 Mark
Which is the only alcohol that can be prepared by the indirect hydration of alken?
AnswerAlkene is treated with sulfuric acid to give alkyl sulphate esters. In the case of ethanol production, this step can be written:
$\mathrm{H}_2 \mathrm{SO}_4+\mathrm{C}_2 \mathrm{H}_4 \rightarrow \mathrm{C}_2 \mathrm{H}_5-\mathrm{O}-\mathrm{SO}_3 \mathrm{H}$
Subsequently, this sulphate ester is hydrolyzed to regenerate sulphuric acid and release ethanol:
$\mathrm{C}_2 \mathrm{H}_5-\mathrm{O}-\mathrm{SO}_3 \mathrm{H}+\mathrm{H}_2 \mathrm{O} \rightarrow \mathrm{H}_2 \mathrm{SO}_4+\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}$
This two step route is called the "indirect process".
Only in case of ethane it will produce ethyl alcohol while in case of other alkenes product is according to Markovnikov′s Rule.
Methyl alcohol can't be produced by indirect hydration of alkene.
View full question & answer→MCQ 791 Mark
Which of the following alcohol has highest solubility in water?
AnswerMore the number of hydroxyl groups in a compound more is the tendency to form hydrogen bonds with water and hence, more will be the solubility.
Thus, among the given, glycerol, because of the presence of more number of hydroxyl groups, readily dissolves in water.
View full question & answer→MCQ 801 Mark
The best method to prepare $3-$methylbutan$-2-o$l from $3-$methylbut$-1-ene$ is:
- ✓
Addition of water in presence of dil. $\ce{H_2SO_4}$.
- B
Addition of $\text{HCI}$ followed by reaction with dil. $\text{NaOH}.$
- C
Hydroboration $-$ oxidation reaction.
- D
Reimer $-$ Tiemann reaction.
AnswerCorrect option: A. Addition of water in presence of dil. $\ce{H_2SO_4}$.
To prepare $3-$methylbutan$-2-ol$ from $3-$methylbut$-1-$ene shouls involve Markovnikov's addition of $\text{H−OH}$ across double bond.
Addition of water in presence of dil. $\ce{H_2SO_4}$ follows Markovnikov's addition of $\text{H−OH}$ across the alkene.
Addition of $\text{HCI}$ followed by reaction with dil$. \text{NaOH}$ to an alkene can give substitution and elimination product after alkyl halide formation.
Hydroboration$-$oxidation reaction follows Anti$-$Markovnikov's addition of $\text{H−OH}.$
Reimer $-$ Tiemann reaction is a chemical reaction used for the ortho$-$formylation of phenols.
Thus the best method to prepare $3-$methylbutan$-2-ol$ from $3-$methylbut$-1-$ene is the addition of water in presence of dil$. \ce{H_2SO_4}$.
View full question & answer→MCQ 811 Mark
Ether is formed when alkyl halide is treated with sodium alkoxide. This method is known as:
AnswerEther is formed when alkyl halide is treated with sodium alkoxide. This method is known as Williamson synthesis.
For example, methyl iodide reacts with sodium methoxide to form dimethyl ether.
$\ce{CH_3−I + CH_3−O−Na \rightarrow CH_3−O−CH_3+ NaI}$
View full question & answer→MCQ 821 Mark
Ether is obtained from ethyl alcohol in presence of $\ce{H_2SO_4}$ at?
- A
$113K$
- B
$443K$
- ✓
$413K$
- D
$213K$
AnswerCorrect option: C. $413K$
Acid$-$catalyzed method of preparing symmetrical ethers from primary alcohols is temperature dependence. At $110^\circ 413KC$ or $383K$ to $130∘C$ or $403K,$ a $\ce{SN^2}$ reaction of the alcohol conjugate acid leads to an ether product. At higher temperatures $($over $150^\circ C$ or $423K)$ an $E_2$ elimination takes place and instead of ether, an alkene is obtained.
Thus, Ether is obtained from ethyl alcohol in presence of $\ce{H_2SO_4}$ at $413K.$
View full question & answer→MCQ 831 Mark
Phenol on reaction with $NH_3$ gives:
AnswerPhenol on reaction with ammonia gives aniline. In this reaction$, -OH$ group is replaced with $−NH_2$ group.
View full question & answer→MCQ 841 Mark
Phenol reacts with alkali to give:
AnswerCorrect option: C. Both $a$ and $b$
Phenol is weakly acidic in nature. Hence when it reacts with alkali, it gives a salt and water i.e. the neutralization reaction takes place.
View full question & answer→MCQ 851 Mark
Heating together of sodium ethoxide and ethyl iodide will give:
AnswerWilliamson's ether synthesis reaction.
View full question & answer→MCQ 861 Mark
An alkene $\ce{CH_3CH=CH_2}$ is treated with $\ce{B_2H_6}$ in presence of $\ce{H_2O_2}$. The final product formed is:
- A
$ \mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CHO} $
- B
$ \mathrm{CH}_3 \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_3 $
- ✓
$ \mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CH}_2 \mathrm{OH} $
- D
$ \left(\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CH}_2\right)_3 \mathrm{~B} $
AnswerCorrect option: C. $ \mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CH}_2 \mathrm{OH} $
Hydroboration$-$oxidation reaction follows anti$-$Markovnikov's addition of $\text{H−OH}$ across $C=C$ to give alcohol.
Thus an alkene $\ce{CH_3CH=CH_2}$ when treated with $\ce{B_2H_6}$ in presence of $\ce{H_2O_2}$ will yield the final product as $ \mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CH}_2 \mathrm{OH} $
View full question & answer→MCQ 871 Mark
Select the correct order of boiling point:
- A
diethyl ether $> n-$butyl alcohol $> n-$butaraldehyde $> n-$pentane.
- ✓
$n-$butyl alcohol $> n-$butaraldehyde $> n-$pentane $>$ diethylether.
- C
$n-$pentane $> n-$butaraldehyde $> n-$butyl alcohol $>$ diethylether.
- D
$n-$butyl alcohol $> n-$butaraldehyde $>$ diethylether $> n-$pentane.
AnswerCorrect option: B. $n-$butyl alcohol $> n-$butaraldehyde $> n-$pentane $>$ diethylether.
As we know that the higher the extent of intermolecular Hydrogen bonding in a molecule, the higher its boiling point becomes.
By that logic$, n-$butyl alcohol will have a higher boiling point than $n-$butyraldehyde due to the presence of more extensive $H-$bonding.
Again, there is no $H-$bonding present in both diethyl ether and $n-$pentane. But as $n-$pentane has a higher molecular weight than that of diethyl ether, it will possess a higher boiling point.
View full question & answer→MCQ 881 Mark
What is the functional group in alcohol?
- ✓
$−OH$
- B
$−CN$
- C
$−NC$
- D
$-\mathrm{NH}_2$
Answer$-OH\ ($Hydroxyl group$)$ is the functional group of alcohol. Because, if we add $-OH$ to a Methyl group $\left(-\mathrm{CH}_3\right)$, it will be converted to Methyl alcohol $\left(\mathrm{CH}_3 \mathrm{OH}\right)$.
View full question & answer→MCQ 891 Mark
The nature of $2, 4, 6-$trinitrophenol is:
Answer$2, 4, 6−$trinitrophenol is picric acid. It is acidic in nature. The withdrawing nature of $\mathrm{NO}_2$ groups make the compound acidic.
View full question & answer→MCQ 901 Mark
Isopropyl benzene on air oxidation in the presence of dilute acid gives:
- A
$\mathrm{C}_6 \mathrm{H}_5 \mathrm{COOH}$
- B
$\mathrm{C}_6 \mathrm{H}_5 \mathrm{COCH}_3$
- C
$\mathrm{C}_6 \mathrm{H}_5 \mathrm{CHO}$
- ✓
$\mathrm{C}_6 \mathrm{H}_5 \mathrm{OH}$
AnswerCorrect option: D. $\mathrm{C}_6 \mathrm{H}_5 \mathrm{OH}$
View full question & answer→MCQ 911 Mark
The correct $\text{IUPAC}$ name of the compound is?
- A
$2-$ethyl$-1-$chlorocyclohexanol.
- B
$4-$chloro$-5-$ethylcyclhexanol.
- C
$4-$hydroxy$-2-$ethyl$-1-$chlorocycloheane.
- ✓
$4$ chloro$-3-$ethylcyclohexanol.
AnswerCorrect option: D. $4$ chloro$-3-$ethylcyclohexanol.
$-OH$ group is given preference over $Cl$ group so$, 1$ number to carbon attach to $-OH$ group
so$, 4-$chloro$-3$ ethyl$-$cyclohexan $-1-ol.$
View full question & answer→MCQ 921 Mark
Dehydration of the following in increasing order is:
AnswerPhenol $(I)$ is stable aromatic compound. So it is most stable. The diene $(IV)$ undergoes quick dehydration because it will form stable phenol. The alkene $\text{(III)}$ undergoes dehydration. less readily because it gives a more stable diene. Alcohol $(II)$ undergoes much lesser dehydration to form alkene. So, order is$:\ 4>3>2>1.$
View full question & answer→MCQ 931 Mark
Strength of acidity is in order:
- A
$\ce{II>I}$
- ✓
$\ce{I>II}$
- C
$\ce{I=II}$
- D
AnswerCorrect option: B. $\ce{I>II}$
As we know that the strength of acidity inversely depends upon the $+I$ effect.
Thus, due to $+I$ effect of methyl group $\left(-\mathrm{CH}_3\right), I$ is more acidic than $II.$
Hence the correct order of strength of acidity is $-I>II.$
View full question & answer→MCQ 941 Mark
AnswerMethanol is the contraction of Methyl Alcohol. Methanol may also be called, wood alcohol or wood spirit because it can be produced as a by$-$product of the wood distillation.
View full question & answer→MCQ 951 Mark
Alcohols containing only up to $........$ carbon atoms are completely miscible with water.
AnswerAlcohol$-$containing up to $3−$ carbon atoms are completely miscible with water in all proportions. This is due to the hydrogen bonding with water molecule.
View full question & answer→MCQ 961 Mark
Butane has a $.......$ boiling point to that of propanol.
AnswerThe molecules of butane are held together by weak vander Waals forces of attraction, while those of propanol are held together by stronger intermolecular hydrogen bonding.
Therefore, the boiling point of propanol is much higher than of butane.
View full question & answer→MCQ 971 Mark
The bond angle of the bond $\text{C−O−C}$ in methoxy methane is:
- ✓
$111.7$
- B
$109$
- C
$108.9$
- D
$180$
AnswerCorrect option: A. $111.7$
Ethers feature $\mathrm{C}-\mathrm{O}-\mathrm{C}$ linkage defined by a bond angle of about $110^{\circ}$ and $\mathrm{C}-\mathrm{O}$ bond length of about $140\ pm .$
In methoxymethane, the bond angle is $111.7^{\circ}$. Methoxymethane show positive deviation in the bond angle. This is basically due to the steric crowding on carbon atoms of methyl group.
Due to the crowding, the repulsion between bond pair of carbons and lone pair of oxygen is low. Thus, the bond angle of methoxymethane is $111.7^0$. View full question & answer→MCQ 981 Mark
The $\text{IUPAC}$ name is:
AnswerCorrect option: B. $3-$Methyl$-3-$pentanol
Hence $\text{IUPAC}$ name is $3-$methyl$-3-$pentanol.
View full question & answer→MCQ 991 Mark
Which of the following can not be formed by hydrolysis of alkenes?
AnswerHydrolysis of alkene mainly gives alcohol simplest alkene that is ethane on hydrolysis gives ethanol. So Methanol cannot be formed by hydrolysis of alkene.
View full question & answer→MCQ 1001 Mark
The strongest acid in the following compounds is:
- A
- B
$p-$cresol
- C
$m-$nitrophenol
- ✓
$p-$nitrophenol
AnswerCorrect option: D. $p-$nitrophenol
$o-$nitro phenol participates in intra$-$molecular $H−$bonding, which makes it less acidic than $p-$nitro phenol. Since acidic strength depends on the stability of negative ion after removal of acidic $H, -\mathrm{NO}_2$ group in $o$ and $p$ position provides $−M$ effect as the negative charge delocalizes.
View full question & answer→MCQ 1011 Mark
The product formed by decolourization of $\mathrm{KMnO}_4$ by ethylene is $......$ which is used as $.....$
- A
- B
- ✓
ethylene glycol, antifreeze
- D
AnswerCorrect option: C. ethylene glycol, antifreeze
When ethylene react with $\mathrm{KMnO}_4,$ than pink colour of $\mathrm{KMnO}_4$ gets disappear and ethylene gets converted with ethylene glycol.
View full question & answer→MCQ 1021 Mark
Which compound is the most soluble in water?
AnswerAmong given compounds, ethylene glycol $\left(\mathrm{HO}-\mathrm{CH}_2-\mathrm{CH}_2-\mathrm{OH}\right)$ is the most soluble in water. Ethylene glycol has two hydroxy groups both of which form hydrogen bonds with water. Greater is the number of hydrogen bonds, greater is the extent of hydrogen bonding and greater is the solubility in water.
View full question & answer→MCQ 1031 Mark
Which of the following is not characteristic of alcohols:
- A
They are lighter than water.
- B
Their boiling points rise fairly uniformly with increasing molecular weight.
- ✓
Lower members are insoluble in water and organic solvents but solubility regularly increases with molecular weight.
- D
Lower members have pleasant smell and burning taste, while higher members are odourless and tasteless.
AnswerCorrect option: C. Lower members are insoluble in water and organic solvents but solubility regularly increases with molecular weight.
Lower members are soluble in water and solubility decreases with increasing molecular mass because the length of the hydrophobic chain increases.
View full question & answer→MCQ 1041 Mark
With ethoxyethane which compound is miscible to almost the same extent?
- A
- B
- ✓
Butan$-1-ol$
- D
Propan$-1-ol$
AnswerCorrect option: C. Butan$-1-ol$
Ethoxyethane is an ether group which is miscible to the alcohol that is Butan $−1−ol.$ This is because they have the same molecular mass.
View full question & answer→MCQ 1051 Mark
Alcohols containing only up to $.......$ carbon atoms are completely miscible with water.
AnswerHydroxyl group makes the alcohol molecule polar and these are used as protic solvents. Two opposing solubility trends in alcohols are the tendency of the polar $OH$ to promote solubility in water and the tendency of the carbon chain to resist it.
So, methanol, ethanol, propanol are miscible in water as the $OH$ group overcomes the short carbon chain.
View full question & answer→MCQ 1061 Mark
Which among the following reactions does not give methyl alcohol?
AnswerCorrect option: A. The reaction of ethylene with $\mathrm{H}_2 \mathrm{SO}_4$ at $80^{\circ} \mathrm{C}$
The reaction of ethylene with $\mathrm{H}_2 \mathrm{SO}_4$ at $80^{\circ} \mathrm{C}$ gives ethyl hydrogensulphate.
$\mathrm{CH}_2=\mathrm{CH}_2+\mathrm{H}_2 \mathrm{SO}_4 \rightarrow \mathrm{CH}_3 \mathrm{CH}_2 \mathrm{OSO}_2 \mathrm{OH}$
Water gas (carbon monoxide and hydrogen) at high temperature gives methanol.
$\mathrm{CO}+2 \mathrm{H}_2 \rightarrow \mathrm{CH}_3 \mathrm{OH}$.
Alkaline hydrolysis of methyl bromide gives methanol
$\mathrm{CH}_3 \mathrm{Br}+\mathrm{H}_2 \mathrm{O} \rightarrow \mathrm{CH}_3 \mathrm{OH}+\mathrm{HBr}$.
View full question & answer→MCQ 1071 Mark
$\text{IUPAC}$ name of $m-$cresol is $......$
- ✓
$3-$methylphenol.
- B
$3-$chlorophenol.
- C
$3-$methoxyphenol.
- D
Benzene$-1,3-$diol.
AnswerCorrect option: A. $3-$methylphenol.
$-OH$ is functional group and $-CH_3$ is substituent.
$\text{IUPAC}$ name$:\ 3-$methylphenol. View full question & answer→MCQ 1081 Mark
The correct reactivity order of alcohols towards $H−X$ will be:
- A
$\text{II>I>III>IV}$
- B
$\text{IV>III>II>I}$
- C
$\text{II>IV>I>III}$
- ✓
$\text{II>IV>III>I}$
AnswerCorrect option: D. $\text{II>IV>III>I}$
The correct reactivity order of alcohols towards $H−X$ will be $\text{II>IV>III>I}$
Alcohol $II$ has maximum reactivity as the carbocation formed will be stabilized by resonance with adjacent $C=C$ double Bond.
Alcohol $I$ has minimum reactivity as the carbocation formed will have positive charge on $sp^2$ carbon atom.
Alcohol $IV$ is more reactive than alcohol $III$ because alcohol $IV$ gives secondary carbocation whereas alcohol $III$ gives primary carbocation.
Secondary carbocation is more stable than primary carbocation.
View full question & answer→MCQ 1091 Mark
When alkyl halide is heated with dry $\ce{Ag_2O},$ it produces:
AnswerAlkyl halide on reaction with dry silver oxide gives ether.
$\ce{2RX + Ag_2O \longrightarrow R−O−R + 2AgX}$
View full question & answer→MCQ 1101 Mark
When ethyl alcohol reacts with nitric acid, it forms:
Answer$\mathrm{CH}_3-\mathrm{CH}_2-\mathrm{OH}+\mathrm{HNO}_3 \rightarrow \mathrm{C}_2 \mathrm{H}_5 \mathrm{NO}_3+\mathrm{H}_2 \mathrm{O}$
View full question & answer→MCQ 1111 Mark
In iodine charge transfer test the color of ether compound formed is:
AnswerEther forms charge transfer complexes with Iodine to give a brown solution.
$\ce{R−O−R\ ′ \longrightarrow R′I ^−+ RI + H_2O}$
View full question & answer→MCQ 1121 Mark
Which of the following reacts fastly with $Na?$
- ✓
$1^\circ $ alcohol
- B
$2^\circ $ alcohol
- C
$3^\circ $ alcohol
- D
The reactivity of all is equal.
AnswerCorrect option: A. $1^\circ $ alcohol
$1^\circ $ alcohols are more acidic than $ 2^\circ$ and $3^\circ$ alcohols and hence they react faster with Na.
View full question & answer→MCQ 1131 Mark
On boiling with concentrated hydrobromic acid, phenyl ethyl ether will yield:
- ✓
Phenol and ethyl bromide.
- B
- C
Bromobenzene and ethanol.
- D
AnswerCorrect option: A. Phenol and ethyl bromide.
On boiling with concentrated hydrobromic acid, phenyl ethyl ether will yield phenol and ethyl bromide.
View full question & answer→MCQ 1141 Mark
What amount of bromine will be required to convert $2g$ of phenol into $2, 4, 6−$tribromophenol?
- A
$4.00$
- B
$6.00$
- ✓
$10.22$
- D
$20.44$
AnswerCorrect option: C. $10.22$
Write equation for chemical change, find molecular masses of reactants and products and solve it.
Molecular weight of phenol
$= 12 \times 6 + 1 \times 6 + 16 = 94$
Molecular wt. of $Br_2 = 3 \times 160 = 480$
$\because 94$ of phenol requires $=480g$ of $Br_2$
$\therefore 2g$ of phenol requires $= \frac{480}{94}\times 2=10.22\text{g}$
The correct answer is $10.22g$
View full question & answer→MCQ 1151 Mark
The $\text{IUPAC}$ name for $\mathrm{CH}_3 \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_2 \mathrm{C}\left(\mathrm{CH}_3\right)_2 \mathrm{OH}$ is:
- A
$1, 1-$dimethyl$-1, 3-$butanediol
- ✓
$2-$methyl$-2, 4$ pentanediol
- C
$4-$methyl$-2 4-$pentanediol
- D
$1, 3, 3-$ trimethyl $1-1, 3-$propanediol
AnswerCorrect option: B. $2-$methyl$-2, 4$ pentanediol
The compound has $2$ alcohol groups at $C-2$ positions on both the sides. From this point we can not say from where to start numbering.
But if we number from right hand side there is also a methyl group at $C-2$ position. So we start number from right hand side.
Since there are two alcoholic group, we use suffix "diol".
Thus $\text{IUPAC}$ name is$:\ 2-$Methyl$-2,4$ pentanediol.
View full question & answer→MCQ 1161 Mark
Vapours of an alcohol $X$ when passed over hot reduced copper, produce an alkene, the alcohol is:
AnswerGiven$:\ \ce{X(ROH) + Cu}($hot$) \rightarrow $ alkene
Primary alcohol passed over $Cu$ at $300^\circ C$ is dehydrogenated to aldehydes and hydrogen gas liberates.
Secondary alcohols are dehydrogenated to ketones with liberation of hydrogen gas
Tertiary alcohol is dehydrated to alkene.
This method can therefore be used to distinguish between primary, secondary and tertiary alcohol
Thus $X$ should be a tertiary alcohol.
View full question & answer→MCQ 1171 Mark
$\text{IUPAC}$ name of the compound $\text{CH}_3-\text{CH}-\text{OCH}_3 \\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ | \\ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{CH}_3$ is $.......$
AnswerCorrect option: C. $2-$methoxypropane.
$\text{IUPAC}$ name of the above compound is $2-$methoxypropane. View full question & answer→MCQ 1181 Mark
The suffix used in the nomenclature of alcohol is:
- A
$'al\ '$
- ✓
$'ol\ '$
- C
$'yl\ '$
- D
AnswerCorrect option: B. $'ol\ '$
According to $\text{IUPAC}$ system suffix for alcohols is $'ol\ '.$
View full question & answer→MCQ 1191 Mark
Mark the correct order of decreasing acid strength of the following compounds.
- A
$\text{e > d > b > a > c.}$
- ✓
$\text{b > d > a > c > e}.$
- C
$\text{d > e > c > b > a.}$
- D
$\text{e > d > c > b > a}.$
AnswerCorrect option: B. $\text{b > d > a > c > e}.$
$-NO_2$ is an electron withdrawing group which increases the acidity of phenol and the effect is more pronounced at ortho and para positions. Similarly methoxy group is an electron releasing group which decreases the acidity of phenol and the effect is more pronounced at ortho and para positions. View full question & answer→MCQ 1201 Mark
Baeyers reagent is $\ce{KMnO_4}$ in which medium?
- ✓
- B
- C
- D
Alkaline and acidified both
AnswerBaeyer's reagent, named after the German organic chemist Adolf von Baeyer, is used in organic chemistry as a qualitative test for the presence of unsaturation, such as double bonds.
Baeyer's reagent is an alkaline solution of cold potassium permanganate, which is a powerful oxidant making this a redox reaction.
View full question & answer→MCQ 1211 Mark
The general formula for alcohol series is $\mathrm{C_n} \mathrm{H_{2 n+1}} \mathrm{OH}$. Which is the formula for alcohol contains four carbon?
- A
$\mathrm{C}_5 \mathrm{H}_{11} \mathrm{OH}$
- ✓
$\mathrm{C}_4 \mathrm{H}_9 \mathrm{OH}$
- C
$\mathrm{C}_4 \mathrm{H}_8 \mathrm{OH}$
- D
$\mathrm{C}_3 \mathrm{H}_8 \mathrm{OH}$
AnswerCorrect option: B. $\mathrm{C}_4 \mathrm{H}_9 \mathrm{OH}$
The general formula for alcohol series is $\mathrm{C}_n \mathrm{H}_{2 n+1} \mathrm{OH}$. The formula for alcohol contains four carbon atoms is
$\mathrm{C_n} \mathrm{H}_{2 \mathrm{n}+1} \mathrm{OH}=\mathrm{C}_4 \mathrm{H}_{2(4)+1} \mathrm{OH}=\mathrm{C}_4 \mathrm{H}_{8+1} \mathrm{OH}=\mathrm{C}_4 \mathrm{H}_9 \mathrm{OH}$.
View full question & answer→MCQ 1221 Mark
The order of boiling point of primary $(1),$ secondary $(2)$ and tertiary $(3)$ alcohols is:
- ✓
$\ce{1 > 2 > 3}$
- B
$\ce{3 > 2 > 1}$
- C
$\ce{2 > 1 > 3}$
- D
$\ce{2 > 3 > 1}$
AnswerCorrect option: A. $\ce{1 > 2 > 3}$
The order of the boiling point is Primary $(1) >$ secondary $(2) >$ tertiary $(3)$ alcohol
This is because the surface area decreases and the van Der waals forces decreases.
View full question & answer→MCQ 1231 Mark
Solubility of alcohols in water is $.......$ to that of hydrocarbons of comparable molecular masses.
AnswerSince alcohols can participate in $H−$bonding while hydrocarbons cannot, alcohols are able to interact with water molecules more easily than hydrocarbons of comparable molecular masses.
Hence alcohols possess greater solubility in water than hydrocarbons of comparable molecular masses.
View full question & answer→MCQ 1241 Mark
Which of the following gives the most stable carbocation by dehydration?
- A
$\ce{(CH_3)_2CH−OH}$
- ✓
$\ce{(CH_3)_3C−OH}$
- C
$\ce{CH_3−CH_2−OH}$
- D
$\ce{CH_2=CH−OH}$
AnswerCorrect option: B. $\ce{(CH_3)_3C−OH}$
Easy dehydration of compound depends on the following parameters.
Resonance stabilized carbocation formation after dehydration.
$+M$ and $+I$ effect of an adjacent group of atoms.
The number of α hydrogen attached with carbocation.
Compound $B$ is the one that is most readily dehydrated because it forms a tertiary carbocation with nine $\alpha−H$ atoms which makes it the most stable carbocation.
The dehydration reaction is shown as below;
View full question & answer→MCQ 1251 Mark
What is the correct order of reactivity of alcohols in the following reaction$?\ \text{R}-\text{OH}+\text{HCL}\xrightarrow{\text{ZnCl}_2}\text{R}-\text{Cl}+\text{H}_2\text{O}$
- A
$1^\circ > 2^\circ > 3^\circ $
- B
$1^\circ < 2^\circ > 3^\circ $
- ✓
$3^\circ > 2^\circ > 1^\circ $
- D
$3^\circ > 1^\circ > 2^\circ $
AnswerCorrect option: C. $3^\circ > 2^\circ > 1^\circ $
This reaction is a type of nucleophilic substitution reaction in which$ -OH$ group is replaced by $-Cl.$ The intermediate formed by tertiary alcohol is more stable as carbocation is more stable than primary and secondary carbocation. Thus, the order of reactivity of alcohol will be $3^\circ > 2^\circ > 1^\circ .$
View full question & answer→MCQ 1261 Mark
The high boiling point of ethanol $(78.2^\circ C)$ compared to dimethyl ether $(−23.6^\circ C),$ though both having the same molecular formula $\ce{C_2H_6O},$ is due to:
- ✓
- B
- C
co-ordinate covalent bonding
- D
AnswerThe high boiling point of ethanol $(78.2^\circ C)$ compared to dimethyl ether $(−23.6^\circ C),$ though both having the same molecular formula $\ce{C_2H_6O},$ is due to Hydrogen bonding.
Hydrogen bonding is observed when $H$ atom is attached to more electronegative $N, F$ or $O$ atom.
Ethanol molecules are associated due to hydrogen bonding. This results in higher boiling point.
However, hydrogen bonding is not possible in dimethyl ether.
View full question & answer→MCQ 1271 Mark
Which of the following alcohols is the least soluble in water?
- A
- B
$1-$Propanol
- C
$1-$Butanol
- ✓
$1-$Pentanol
AnswerCorrect option: D. $1-$Pentanol
Alcohols are soluble in water due to hydrogen bonding. However, as the length of carbon chain increases, the extent of hydrogen bonding decreases due to bulky chain.
According to this$, 1−$pentanol will be the least soluble in water, among the other given alcohols.
View full question & answer→MCQ 1281 Mark
Which of the following name does not fit a real name?
AnswerCorrect option: A. $3 -$methyl $3 -$hexanone
View full question & answer→MCQ 1291 Mark
Which of the following is used in the manufacture of ethanol?
- A
$\mathrm{C}_2 \mathrm{H}_6$
- B
$\mathrm{C}_2 \mathrm{H}_2$
- C
$\mathrm{CH}_4$
- ✓
$\mathrm{C}_2 \mathrm{H}_4$
AnswerCorrect option: D. $\mathrm{C}_2 \mathrm{H}_4$
Alcohols can be prepared by the hydration of alkenes. Therefore, ethanol $\left(\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}\right)$ can be prepared from the corresponding alkene$; \mathrm{C}_2 \mathrm{H}_4$ as:
$\mathrm{CH}_2=\mathrm{CH}_2+\mathrm{H}_2 \mathrm{O} \rightarrow \mathrm{H}+\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{OH}$
View full question & answer→MCQ 1301 Mark
Which of the following has a higher boiling point?
- ✓
- B
- C
Both of them have similar boiling point
- D
AnswerThere is a large difference between boiling points of butanol and butanal, although they have almost the same solubility in water.
Butanol contains $-OH$ group and can form hydrogen bonds. Hence, the molecules are associated. A large amount of energy is required to break the association.
Hence, butanol has a higher boiling point. Hydrogen bonding is not possible in butanal.
View full question & answer→MCQ 1311 Mark
Compound $\mathrm{C}_2 \mathrm{H}_6 \mathrm{O}$ has two isomers $X$ and $Y.$ On reaction with $HI, X$ gives alkyl iodide and water while $Y$ gives alkyl iodide and alcohol.Compounds $X$ and $Y$ are respectively:
- A
$\mathrm{C}_2 \mathrm{H}_5 \mathrm{OC}_2 \mathrm{H}_5$ and $\mathrm{CH}_3 \mathrm{OC}_2 \mathrm{H}_5$
- B
$\mathrm{CH}_3 \mathrm{OCH}_3$ and $\mathrm{C}_2 \mathrm{H}_5 \mathrm{OCH}_3$
- ✓
$\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}$ and $\mathrm{CH}_3 \mathrm{OCH}_3$
- D
$\mathrm{CH}_3 \mathrm{OH}$ and $\mathrm{CH}_3 \mathrm{OCH}_3$
AnswerCorrect option: C. $\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}$ and $\mathrm{CH}_3 \mathrm{OCH}_3$
$(X):\ \mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}+\mathrm{HI} \rightarrow \mathrm{C}_2 \mathrm{H}_5 \mathrm{I}+\mathrm{H}_2 \mathrm{O}$
$(Y):\ \mathrm{CH}_3 \mathrm{OCH}_3+\mathrm{HI} \rightarrow \mathrm{CH}_3 \mathrm{I}+\mathrm{CH}_3 \mathrm{OH}$
View full question & answer→MCQ 1321 Mark
The correct decreasing order of dehydration of following alcohols with conc$. \mathrm{H}_2 \mathrm{SO}_4$ is:
- A
$\text{C > A > B > D}$
- B
$\text{D > A > C > B}$
- C
$\text{A > B > C > D}$
- ✓
$\text{D > C > A > B}$
AnswerCorrect option: D. $\text{D > C > A > B}$
Dehydration order will include $D$ first because after dehydration aromatic compound$($stable$)$ is formed . In this way, the order is arranged according to the stability of the compound formed.
View full question & answer→MCQ 1331 Mark
Trivial name of methanol is $......$
AnswerMethanol is known as methyl alcohol, wood alcohol, wood naphtha or wood spirit because it was once produced as a byproduct of the destructive distillation of wood.
View full question & answer→MCQ 1341 Mark
Which of the following alcohols is dehydrated most easily with conc$. \mathrm{H}_2 \mathrm{SO}_4$?
- A
$\text {p}-\mathrm{O}_2 \mathrm{NC}_6 \mathrm{H}_4 \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_3$
- B
$\text { p }-\mathrm{ClC}_6 \mathrm{H}_4 \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_3$
- ✓
$\text { p }-\mathrm{CH}_3 \mathrm{OC}_6 \mathrm{H}_4 \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_3$
- D
$\mathrm{C}_3 \mathrm{H}_5 \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_3$
AnswerCorrect option: C. $\text { p }-\mathrm{CH}_3 \mathrm{OC}_6 \mathrm{H}_4 \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_3$
The dehydration reaction is as: Alcohol $+\mathrm{H}_2 \mathrm{SO}_4 \rightarrow$ alkene is an elimination reaction that goes via carbocation formation.
Higher is the stability of carbocation more easily it can be dehydrated.
The corresponding carbocations formed by given molecules are shown in the figure.
Due to the $--$Inductive effect $(-I)$ and $--$Mesomeric effect $(-M)$ of $\mathrm{NO}_2$ group, it will decrease the electron density on benzene and will, therefore, destabilise the carbocation the most and makes it difficult to dehydrate.
In case of $\mathrm{p}-\mathrm{ClC}_6 \mathrm{H}_4 \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_3$, the $Cl$ has stronger $-l$ effect $($due to high electronegativity$)$ than its $+M$ effect $($due to a lone pair of electrons$)$ thus will destabilise the carbocation and unfavour dehydration.
In case of $\mathrm{p}-\mathrm{CH}_3 \mathrm{OC}_6 \mathrm{H}_4 \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_3$, the $\mathrm{CH}_3 \mathrm{O}$ has the stronger $+M$ effect due to a lone pair of electrons on $O$ than its $-I$ effect and will stabilise the carbocation by increasing the electron density in the benzene ring and will favour dehydration.
$\mathrm{C}_3 \mathrm{H}_5 \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_3$ has $+1$ effect that stabilises the carbocation but its impact is lower than the $+-$ mesomeric effect of the methoxy group.
The alcohol that is dehydrated most easily with conc. $\mathrm{H}_2 \mathrm{SO}_4$ is $\mathrm{p}-\mathrm{CH}_3 \mathrm{OC}_6 \mathrm{H}_4 \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_3$
View full question & answer→MCQ 1351 Mark
Rate of dehydration when given compound is treated with conc$, \mathrm{H}_2 \mathrm{SO}_4$.
- ✓
$\text{P > Q > R > S}$
- B
$\text{Q > P > R > S}$
- C
$\text{R > Q > P > S}$
- D
$\text{R > Q > S > P}$
AnswerCorrect option: A. $\text{P > Q > R > S}$
View full question & answer→MCQ 1361 Mark
The compound $A$ on treatment with $Na$ gives $B,$ and with $\mathrm{PCI}_5$ gives $C. B$ and $C$ react together to give diethyl ether$. A, B$ and $C$ are in the order.
- ✓
$\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}, \mathrm{C}_2 \mathrm{H}_5 \mathrm{ONa}, \mathrm{C}_2 \mathrm{H}_5 \mathrm{Cl}$
- B
$\mathrm{C}_2 \mathrm{H}_5 \mathrm{Cl}, \mathrm{C}_2 \mathrm{H}_6, \mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}$
- C
$\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}, \mathrm{C}_2 \mathrm{H}_5 \mathrm{Cl}, \mathrm{C}_2 \mathrm{H}_5 \mathrm{ONa}$
- D
$\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}, \mathrm{C}_2 \mathrm{H}_6, \mathrm{C}_2 \mathrm{H}_5 \mathrm{Cl}$
AnswerCorrect option: A. $\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}, \mathrm{C}_2 \mathrm{H}_5 \mathrm{ONa}, \mathrm{C}_2 \mathrm{H}_5 \mathrm{Cl}$
View full question & answer→MCQ 1371 Mark
The number of carbon atoms present in a molecule of simple ether is:
AnswerSimple ethers have the same alkyl groups on both sides of the Oxygen atom.
Like$,\ce{CH_3−O−CH_3}$
Thus, the number of carbon atoms is always even.
View full question & answer→MCQ 1381 Mark
Methanol is called as Marine Methanol beacuse:
- A
It is an essential compound for marine life.
- B
It is mostly obtained from deep sea bed.
- ✓
It is used as a marine fuel.
- D
It serves as a signal indicator for big ships on burning.
AnswerCorrect option: C. It is used as a marine fuel.
Currently, methanol is being developed and utilized as a marine fuel. Interest in methanol as a ship fuel is growing in response to international regulatory changes and cost advantages relative to other fuels. Methanol is an alternative which is sulphur free, has low emissions; perhaps three to four times cheaper than marine distillate fuel; and has a higher score on the International Martine Organization $(\text{IMO})$ energy efficiency design index $(\text{EEDI})$ than $\text{LNG}$ or diesel. Globally, Methanol is already in widespread production $(\sim 70$ million tons per annum$)$ for a multitude of chemical and energy applications, and is one of the world’s most widely shipped chemicals.
View full question & answer→MCQ 1391 Mark
Which of the following alcohol on dehydration will produce a pair of isomeric alkene?
- A
propan$-2-ol$
- B
pentan$-3-ol$
- ✓
hexan$-3-ol$
- D
heptan$-4-ol$
AnswerCorrect option: C. hexan$-3-ol$
View full question & answer→MCQ 1401 Mark
Maximum boiling point would be shown by:
AnswerCorrect option: C. $\ce{CH_3−CH_2−CH_2−OH}$
Maximum boiling point would be shown by n propanol$, \ce{CH_3−CH_2−CH_2−OH}$
In $n-$propanol, the molecules are associated due to hydrogen bonding. Hence, the boiling point is higher. In dimethyl ether and diethyl ether, the boiling point is lower as hydrogen bonding is not possible.
The extent of the hydrogen bonding in isopropanol is lower than that in $n-$propanol due to $+I$ effect of two methyl groups.Also, as the degree of branching increases, the boiling point decreases.
View full question & answer→MCQ 1411 Mark
Which of the following represents monohydric alcohol?
- A
$\mathrm{C}_n \mathrm{H}_{2 n} \mathrm{OH}$
- ✓
$\mathrm{C}_n \mathrm{H}_{2 n}+{ }_1 \mathrm{OH}$
- C
$\mathrm{C}_n \mathrm{H}_n \mathrm{O}$
- D
$\mathrm{C}_n \mathrm{H}_n \mathrm{OH}$
AnswerCorrect option: B. $\mathrm{C}_n \mathrm{H}_{2 n}+{ }_1 \mathrm{OH}$
View full question & answer→MCQ 1421 Mark
What is the common name of methyl alcohol?
AnswerMethanol acquired the name wood spirit because it was once produced chiefly by the destructive distillation of wood.
View full question & answer→MCQ 1431 Mark
Which of the following is wood alcohol?
AnswerCorrect option: A. $\mathrm{CH}_3 \mathrm{OH}$
Methanol, also known as methyl alcohol, wood alcohol, wood naphtha, methyl hydrate, or wood spirits, is a chemical with the formula $\mathrm{CH}_3 \mathrm{OH}$.
Methanol acquired the name wood alcohol because it was once produced chiefly by the destructive distillation of wood.
View full question & answer→MCQ 1441 Mark
When $3-$methylbutan$-2-ol$ is treated with $\text{HBr},$ the following reaction takes place. What are the correct steps for formation of the above product?
- A
Formation of carbocation $\rightarrow $ Nucleophilic attack by $\mathrm{Br}^{\ominus}$
- ✓
Formation of carbocation $\rightarrow 1,2$ hydride shift $\rightarrow $ Nucleophilic attack by $\mathrm{Br}^{\ominus}$
- C
Formation of carbocation $\rightarrow 1,2$ methyl shift $\rightarrow $ Nucleophilic attack by $\mathrm{Br}^{\ominus}$
- D
AnswerCorrect option: B. Formation of carbocation $\rightarrow 1,2$ hydride shift $\rightarrow $ Nucleophilic attack by $\mathrm{Br}^{\ominus}$
The reaction $($along with mechanism$)$ for the conversion of $3-$methylbutan$-2-ol$ to $2-$bromo$-2-$methylbutane is as given below.
View full question & answer→MCQ 1451 Mark
Which of the following phenols has lowest solubility in water?
- A
- ✓
$o-$Nitrophenol
- C
$m-$Nitrophenol
- D
$p-$Nitrophenol
AnswerCorrect option: B. $o-$Nitrophenol
$O−$ nitrophenol undergoes creation because of intra$-$moleculer hydrogen bonding. So, it is least soluble.
View full question & answer→MCQ 1461 Mark
Phenol can be distinguished from ethanol by the reactions with $.......$
AnswerCorrect option: D. $a$ and $c$
Phenol reacts with bromine water to give a colourless tribromo derivative and gives a violet coloured complex with $\mathrm{FeCl}_3.$ Ethanol does not give these reactions.
View full question & answer→MCQ 1471 Mark
Give the $\text{IUPAC}$ name of the above compound.
- A
$2-$Bromo $3-$methyl butyric acid.
- B
$2-$Bromo $4-$formyl butane.
- ✓
$3-$Bromo $2-$methyl butanoic acid.
- D
AnswerCorrect option: C. $3-$Bromo $2-$methyl butanoic acid.
View full question & answer→MCQ 1481 Mark
$\text{IUPAC}$ name of the compound $\mathrm{CH}_3-\mathrm{CH}\left(\mathrm{CH}_2 \mathrm{CH}_3\right)-\mathrm{CH}_2-\mathrm{CH}(\mathrm{OH})-\mathrm{CH}_3$ is:
- A
$4-$Ethyl$-2-$pentanol
- ✓
$4-$Methyl$-2-$hexanol
- C
$2-$Ethyl$-2-$pentanol
- D
$3-$Ethyl$-2-$hexanol
AnswerCorrect option: B. $4-$Methyl$-2-$hexanol
Longest carbon chain has $6$ atoms. We number from right hand side as alcohol group at $C-2$ gets least number in this case and suffix used for alcohol is $''-ol\ ''.$ Methyl group is present at $C-4$ position.
Thus$, \text{IUPAC}$ name is $4-$Methyl$-2-$hexanol.
View full question & answer→MCQ 1491 Mark
$.......$ is prepared on a large seals from water gas.
AnswerMethanol is generally prepared on a large scale using water gas. Water gas is also called syn gas is the mixture of $\left(\mathrm{CO}+\mathrm{H}_2\right)$.
View full question & answer→MCQ 1501 Mark
By treating alkylchloride with $aq. \text{KOH}$ produce:
- A
- B
$\text{KCl}$
- C
- ✓
Both $A$ and $B$
AnswerCorrect option: D. Both $A$ and $B$
In the presence of aqueous $\text{KOH},$ alkyl chloride gives the substitution product as alcohol. The reaction can be written as:
$\ce{RCl + KOH(aq) \rightarrow ROH + KCl}$
View full question & answer→MCQ 1511 Mark
Destructive distillation of wood in the laboratory will result in the formation of:
AnswerMethanol acquired the name "wood spirit" because it was once produced chiefly as a byproduct of the destructive distillation of wood.
View full question & answer→MCQ 1521 Mark
Among the four compounds $(i)$ acetone$, (ii)$ propanol$, (iiii)$ methyl acetate and $(iv)$ propionic acid, the two that are isomeric are:
- A
Methyl acetate and acetone
- B
Methyl acetate and propanol
- ✓
Propionic acid and methyl acetate
- D
Propionic acid and acetone
AnswerCorrect option: C. Propionic acid and methyl acetate
Propionic acid and methyl acetate both have same molecular formula $\left(\mathrm{C}_3 \mathrm{H}_6 \mathrm{O}_2\right)$ but different functional groups, so they are isomers.
View full question & answer→MCQ 1531 Mark
Which of the following is a primary alcohol?
AnswerCorrect option: B. $2 -$ Methylpropan $-1- ol$
$\ce{CH_3−CH(CH_3)−CH_2−OH}$ is a primary alcohol as hydroxal group$; -OH$ is attached to the primary carbon.
View full question & answer→MCQ 1541 Mark
$\text{IUPAC}$ name of the tertiary butyl alcohol is:
- A
$1-$butanol
- B
$2-$butanol
- C
$2-$methyl$-1-$propanol
- ✓
$2-$methyl$-2-$propanol
AnswerCorrect option: D. $2-$methyl$-2-$propanol
Above is the structure of tertiary butyl alcohol. Longest carbon chain contains $3$ carbons and one methyl group and one hydroxy group at $2$ position.
Hence, the $\text{IUPAC}$ name of tertiary butyl alcohol is $2-$methyl$-2-$propanol.
View full question & answer→MCQ 1551 Mark
Mark the correct increasing order of reactivity of the following compounds with $\text{HBr/HCl}.$
- A
$\ce{a < b < c.}$
- B
$\ce{b < a < c}.$
- ✓
$\ce{b < c < a}.$
- D
$\ce{c < b < a}.$
AnswerCorrect option: C. $\ce{b < c < a}.$
It is type of nucleophilic substitution reaction followed by $S_{N_1}$ mechanism. $S_{N_1}$ mechanism depends on the stability of carbocation. Presence of electron withdrawing group will decrease the stability of carbocation.
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The only alcohol that can be prepared by the indirect hydration of alkene is:
AnswerExcept for ethyl alcohol, no other primary alcohol can be prepared by this method as the addition of $\ce{H_2SO_4}$ follows Markownikoff's rule. Generally, secondary and tertiary alcohols are obtained.
View full question & answer→MCQ 1571 Mark
$\text{CH}_3\text{−CH}\text{−CH}−\text{CH}_3\\ \ \ \ \ \ \ \ \ \ \ \ \ | \ \ \ \ \ \ \ \ \ \ | \\ \ \ \ \ \ \ \ \ \ \text{OH}\ \ \ \ \ \ \text{OH}\\\\\\\text{IUPAC}$ name of the given compound is:
AnswerCorrect option: A. Butane$-2, 3-$diol
Two functional group $\ce{OH(ol)}$ is attached at carbon no $2 \ \ \ 3$ so its name is butane$−2,3−$diol.
View full question & answer→MCQ 1581 Mark
Arrange the following compounds in increasing order of boiling point.Propan$-1-ol,$ butan$-1-ol,$ butan$-2-ol,$ pentan$-1-ol.$
- ✓
Propan$-1-ol,$ butan$-2-ol,$ butan$-1-ol,$ pentan$-1-ol.$
- B
Propan$-1-ol,$ butan-1-ol, butan$-2-ol,$ pentan$-1-ol.$
- C
Pentan$-1-ol,$ butan$-2-ol,$ butan$-1-ol,$ propan$-1-ol.$
- D
Pentan$-1-ol,$ butan$-1-ol,$ butan$-2-ol,$ propan$-1-ol.$
AnswerCorrect option: A. Propan$-1-ol,$ butan$-2-ol,$ butan$-1-ol,$ pentan$-1-ol.$
The boiling points of alcohols and phenols increase with increase in the number of carbon atoms $($increase in van der Waals forces$.).$ In alcohols, the boiling points decrease with increase of branching in carbon chain $($because of decrease in van der Waals forces with decrease in surface area$.).$
View full question & answer→MCQ 1591 Mark
On reacting with grignard reagent acetone gives?
- A
$1^\circ$ alcohol
- B
$2^\circ$ alcohol
- ✓
$3^\circ$ alcohol
- D
AnswerCorrect option: C. $3^\circ$ alcohol
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