Chemistry M.C.Q (1 Marks)

4. Both A and B

Explanation:
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.

2. Secondary or tertiary alcohol.

Explanation:
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.

1. 5-ethylheptane-2.4-diol

Explanation:
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.

2. Water gas

Explanation:
Syngas is also called as water gas which is a mixture of carbon monoxide and hydrogen.

2. There is intermolecular hydrogen bonding in methanol and no hydrogen bonding in methyl thiol.

Explanation:
Methanol has high boiling point than methyl thiol because there is intermolecular hydrogen bonding in methanol and no hydrogen bonding in methyl thiol.

3. hexan-3-ol

3. 3-Bromo 2-methyl butanoic acid.

4. m-Chlorophenol

Explanation:
Alcohols are less acidic than phenol. Further electron withdrawing group (like - Cl) increases the acidity of phenol, therefore, m-chlorophenol is most.

3. 5-Chlorohexan-2-ol.

Explanation:
Priority will be given to -OH group.

1. 3-cyclohexylpentan-3-ol

Explanation:
The 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.

2. o-nitrophenol.

Explanation:
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.

2. o-nitrophenol

Explanation:
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.

2. IR spectroscopy.

Explanation:
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.

4. Benzyl alcohol.

Explanation:
Monochlorination of toluene in sunlight gives benzyl chloride. On hydrolysis with aq. NaOH, benzyl chloride, shows nucleophilic substitution reaction to give benzyl alcohol.

1. 2-phenylpropan-2-ol

Explanation:
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.

2. iso-Propyl alcohol.

Explanation:
Isopropyl alcohol (IUPAC name 2-propanol), also called isopropanol or dimethyl carbinol.

2. Substitution reaction.

Explanation:
The reaction is a type of nucleophilic substitution reaction in which -Cl group is replaced by -OH.

1. 1-Phenylpropan-2-ol

Explanation:
The 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.

3. Wood spirit

Explanation:
Methanol acquired the name "wood spirit" because it was once produced chiefly as a byproduct of the destructive distillation of wood.

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.

3. An alcohol and an organic acid.

Explanation:

4. Lucas reagent

Explanation:
Primary alcohols react on heating with Lucas elegant.
Secondary alcohols react with Lucas reagent after 5 min tertiary alcohol react immediately with Lucas reagent.

4. H-bonding

Explanation:
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.

4. Mannitol

Explanation:
So, mannitol is a polyhydric alcohol, because it has 6-OH groups. Rest all are monohydric alcohols because they contain single hydroxy group.

2. 2-methylbutan-2-ol

Explanation:
The 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.

4. Glycerol

Explanation:
More 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.

2. n-butyl alcohol > n-butaraldehyde > n-pentane > diethylether.

Explanation:
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.

2. Dihydric alcohol

4. 4 chloro-3-ethylcyclohexanol.

Explanation:
-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.

1. I

Explanation:
Phenol (I) is stable aromatic compound. So it is most stable. The diene (IV) undergoes quick dehydration because it will form stable phenol. The alkene (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.

3. Lower

Explanation:
The 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.

2. 3-Methyl-3-pentanol

Explanation:
Hence IUPAC name is 3-methyl-3-pentanol.

3. 2>3>1

2. Methanol

Explanation:
Methanol 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.

3. Lower members are insoluble in water and organic solvents but solubility regularly increases with molecular weight.

Explanation:
Lower members are soluble in water and solubility decreases with increasing molecular mass because the length of the hydrophobic chain increases.

3. Butan-1-ol

Explanation:
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. 

1. Three

Explanation:
Hydroxyl 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.

2. 3

Explanation:
Alcohol-containing up to 3− carbon atoms are completely miscible with water in all proportions. This is due to the hydrogen bonding with water molecule. 

1. 1° alcohol

Explanation:
1° alcohols are more acidic than 2° and 3° alcohols and hence they react faster with Na.

1. Phenol and ethyl bromide.

Explanation:
On boiling with concentrated hydrobromic acid, phenyl ethyl ether will yield phenol and ethyl bromide.

3. 2-methoxypropane.

Explanation:

IUPAC name of the above compound is 2-methoxypropane.

2. 'ol'

Explanation:
According to IUPAC system suffix for alcohols is ' ol'.

Baeyer'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.

1. 1 > 2 > 3

Explanation:
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.

1. Greater than

Explanation:
Since 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.

3. 3° > 2° > 1°

Explanation:
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° > 2° > 1°.

1. Butanol

Explanation:
There 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.

4. All of the above

Explanation:
Methanol 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.

3. It is used as a marine fuel.

Explanation:
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 (IMO) energy efficiency design index (EEDI)than LNG or diesel. Globally, Methanol is already in widespread production (~70 million tons per annum) for a multitude of chemical and energy applications, and is one of the world’s most widely shipped chemicals.

2. o-Nitrophenol

Explanation:
O− nitrophenol undergoes creation because of intra-moleculer hydrogen bonding. So, it is least soluble.

4. 2-methyl-2-propanol

Explanation:
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 IUPAC name of tertiary butyl alcohol is 2-methyl-2-propanol.

1. Propan-1-ol, butan-2-ol, butan-1-ol, pentan-1-ol

Explanation:
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.).

4. Both A and B

Explanation:
In the presence of aqueous KOH, alkyl chloride gives the substitution product as alcohol. The reaction can be written as:
RCl + KOH(aq) → ROH + KCl

3. Tertiary alcohol

Explanation:
Given: X(ROH) + Cu(hot) → alkene
Primary alcohol passed over Cu at 300°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.

2. Wood spirit

Explanation:
Methanol acquired the name wood spirit because it was once produced chiefly by the destructive distillation of wood.

1. Water gas is used in the manufacture of methyl alcohol.

1. 1 > 2 > 3

Explanation:
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.

4. II>IV>III>I

Explanation:
The correct reactivity order of alcohols towards H−X will be 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 sp2 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.

1. 3 -methyl 3 -hexanone

Explanation:

1. Butane-2, 3-diol

Explanation:
Two functional group OH(ol) is attached at carbon no 2 & 3 so its name is butane−2,3−diol.

Explanation:

2. Water

Explanation:
The 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.

4. Ortho and para position

Explanation:
Electrophilic 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.

1. Phenol

Explanation:
Phenol is used as starting material in the manufacture of nylon, plastics, aspirin, picric acid, and salicylic acid, etc.

2. Central O atom

Explanation:
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.

3. O-cresol < phenol < O- nitrophenol

Explanation:
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.

2. Saytzeff rule

Explanation:
The 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.

4. 1-Pentanol

Explanation:
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.

1. Methanol

Explanation:
Hydrolysis of alkene mainly gives alcohol simplest alkene that is ethane on hydrolysis gives ethanol. So Methanol cannot be formed by hydrolysis of alkene. 

3. Methanol

Explanation:
Methanol acquired the name "wood spirit" because it was once produced chiefly as a byproduct of the destructive distillation of wood.

2. 2-butanol

Explanation:
The 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 2nd carbon , hence the name is 2-butanol.

2. Elimination

Explanation:
When 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.

3. Both a and b

Explanation:
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.

1. Ether

Explanation:
Williamson's ether synthesis reaction.

2. R−O−R

Explanation:
R−O−R is generally the functional group of the ether which is non-polar and does not form hydrogen bonding. 

2. 2−Methylpropan−2−ol

Explanation:
Creakr the molecules mass, higher the boiling point, further greather the branching, lesser the boiling. Point.

4. Rubber and plastics

Explanation:
Rubber and plastic cannot be dissloved in alchol because of nonpolar nature of rubber and plastics.

C

A

B

B