Read the passage given below and answer the following questions: Williamson's synthesis is used for the preparation of symmetrical as well as unsymmerical ether. It is S_N2 reaction mechanism. In Williamson's synthesis, 1º alkyl halide are used for preparation of ethers because 2º and 3º alkyl halide give alkene. Ethers are cleaved by hydrogen halides to alcohol and alkyl halide where alkyl halide is corresponding to that alkyl which has less number of carbon atom (it is because of less steric hindrance). In polar media unsymmetrical ether like tertiary butyl ethyl ether gives ethyl alcohol and tertiary butyl halide as reaction proceeds via carbocation. In these questions (Q. No. i-iv), a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices. 1. Assertion and reason both are correct statements and reason is correct explanation for assertion. 2. Assertion and reason both are correct statements but reason is not correct explanation for assertion. 3. Assertion is correct statement but reason is wrong statement. 4. Assertion is wrong statement but reason is correct statement. 1. Assertion: Rate of reaction of alkyl halide in Williamson's synthesis reaction is 1ºRX > 2ºRX > 3ºRX. Reason: It is a type of bimolecular substitution reaction (S_N2). 2. Assertion: T-Butyl methyl ether is not prepared by the reaction of t-butyl bromide with sodium methoxide. Reason: Sodium methoxide is a weak nucleophile. 3. Assertion: Williamson's synthesis method cannot be used for preparing diphenyl ether. Reason: Aryl halides do not undergo nucleophilic substitution easily. 4. Assertion: When isopropyl bromide is treated with sodium isopropoxide, di-isopropyl ether is obtained as a major product. Reason: With secondary alkyl halides, both substitution and elimination occur. 5. Assertion: Both symmetrical and unsymmetrical ethers can be prepared by Williamson's synthesis. Reason: Williamson's synthesis is an example of nucleophilic substitution reaction.

1. (a) Assertion and reason both are correct statements and reason is correct explanation for assertion. Explanation: Williamson's synthesis occurs by S_N2 mechanism and primary alkyl halides are most reactive in S_N2 reactions. 2. (c) Assertion is correct statement but reason is wrong statement. Explanation: Sodium methoxide is a strong nucleophile. ln presence of a strong base, i.e., sodium methoxide, t-butyl bromide undergoes dehyrohalogenation to form isobutylene. 3. (a) Assertion and reason both are correct statements and reason is correct explanation for assertion. Explanation: Diary! ethers cannot be prepared by Williamson's synthesis since aryl halides do not undergo nucleophilic substitution easily. 4. (d) Assertion is wrong statement but reason is correct statement. Explanation: Since secondary and tertiary alkyl halides prefer to undergo elimination rather th an substitution, therefore, even symmetrical ethers containing secondary and tertiary alkyl groups cannot be prepared in good yields by Williamson synthesis. 5. (b) Assertion and reason both are correct statements but reason is not correct explanation for assertion. Explanation: Depending upon whether the alkyl halide and the alkoxide ion carry the same or different alkyl groups, both symmetrical and unsymmetrical ethers can be prepared by Williamsons synthesis.

Read the passage given below and answer the following questions: …

All chemical reactions involve interaction of atoms and molecules. A large number of atoms/molecules are present in a few gram of any chemical compound varying with their atomic/ molecular masses. To handle such large number conveniently, the mole concept was introduced. All electrochemical cell reactions are also based on mole concept. For example, a $4.0$ molar aqueous solution of NaCl is prepared and 500mL of this solution is electrolysed. This leads to the evolution of chlorine gas at one of the electrode. The amount of products formed can be calculated by using mole concept.
The following questions are multiple choice questions. Choose the most appropriate answer:

The total number of moles of chlorine gas evolved is:

$0.5$
$1.0$
$1.5$
$1.9$

If cathode is a Hg electrode, then the maximum weight of amalgam formed from this solution is:

$300g$
$446g$
$396g$
$296g$

The total charge (coulomb) required for complete electrolysis is:

$186000$
$24125$
$48296$
$193000$

In the electrolysis, the number of moles of electrons involved are:

$2$
$1$
$3$
$4$

In electrolysis of aqueous $NaCl$ solution when Pt electrode is taken, then which gas is liberated at cathode?

$H_2$gas
$Cl_2$gas
$O_2$gas
None of these.

→

Read the passage given below and answer the following questions: Carboxylic acids having an $\alpha$-hydrogen atom when treated with chlorine or bromine in the presence of small amount of red phosphorus gives $\alpha$-halocarboxytic acids. The reaction is known as Hell-Volhard-Zelinsky reaction. $\text{R}-\text{CH}_2-\text{COOH}+\text{X}_2\xrightarrow{\text{red p}}\text{R}-\text{CH}-\text{COOH}\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ |\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{X}\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ (\text{X = Cl, Br)}$ When sodium salt of carboxylic acid is heated with soda lime it loses carbon dioxide and gives hydrocarbon with less number of C-atoms. $\text{R}-\text{COOH}\xrightarrow{\text{NaOH}}\text{R}-\text{COONa}\xrightarrow[\Delta]{\text{NaOH}+\text{CaO}}\text{R}-\text{H}+\text{Na}_2\text{CO}_3\\\text{Carboxylic}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{Sod.}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{Alkane}\\\ \ \ \ \ \text{acid}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{carboxylate}$ In these questions (Q. No. l-iv), a statement of assertion followed by a statement ofreason is given. Choose the correct answer out of the following choices.

Assertion and reason both are correct statements and reason is correct explanation for assertion.
Assertion and reason both are correct statements but reason is not correct explanation for assertion.
Assertion is correct statement but reason is wrong statement.
Assertion is wrong statement but reason is correct statement.

Assertion: $(CH_3)_3CCOOH$ does not give H.V.Z reaction.

Reason: $(CH_3)_3CCOOH$ does not have $\alpha$-hydrogen atom.

Assertion: H.V.Z. reaction involves the treatment of carboxylic acids having $\alpha$-hydrogens with $Cl_2$ or $Br_2$ in presence of small amount of red phosphorus.

Reason: Phosphorus reacts with halogens to form phosphorus trihalides.

Assertion: Propionic acid with $\frac{\text{Br}_2}{\text{P}}$ yields $CH_2Br - CHBr - COOH$.

Reason: Propionic acid has two $\alpha$-hydrogen atoms.

Assertion: $C_6H_5COCH_2COOH$ undergoes decarboxylation easily than $C_6H_5COCH_2COOH$.

Reason: $C_6H_5COCH_2COOH$ is $\beta$-keto acid.

Assertion: On heating 3-methylbutanoic acid with soda lime, isobutane is obtained.

Reason: Soda lime is a mixture of NaOH + CaO in the ratio 3 : 1.

→

Read the passage given below and answer the following questions: Aldehydes and ketones undergo nucleophilic addition reactions.

Carbonyl carbon is electron deficient hence acts as an electrophi le. Nucleophile attacks on the electrophili c carbon atom of the carbonyl group from a direction perpendicular to the plane of the molecule.

ln this process, hybridisation of carbon atom changes from $sp^2$ to $sp^3$ and a tetrahedral alkoxide ion is formed as intermediate. This intermediate captures proton from the reaction medium to give the neutral product. Aldehydes are generally more reactive than ketones in nucleophilic addition reactions. In these questions $(Q. No. l-iv),$ a statement of assertion followed by a statement ofreason is given. Choose the correct answer out of the following choices.

Assertion and reason both are correct statements and reason is correct explanation for assertion.
Assertion and reason both are correct statements but reason is not correct explanation for assertion.
Assertion is correct statement but reason is wrong statement.
Assertion is wrong statement but reason is correct statement.

Assertion: Benzaldehyde is more reactive than ethanal towards nucleophitic attack.

Reason: The overall effect of $-I$ and $+R$ effect of phenyl group decreases the electron density on the carbon atom of $>c=o$ group in benzaldehyde.

Assertion: $(CH_3)_3CCOC(CH_3)_3$ and acetone can be distinguished by the reaction with $NaHSO_3.$

Reason: $HSO_3$ is the nucleophile in bisulphite addition.

Assertion: Ease of nucleophilic addition of the compounds $(I). CH_3CHO$ $(II)$ and $CH_3COCH_3(III)$ is$ I > II > III.$

Reason: Aldehydes and ketones undergo nucleophilic addition reactions.

Assertion: The formation of cyanohydrin from an aldehyde or ketone occurs very slowly with pure $HCN$. The is reaction is catalysed by a base.

Reason: Base generates $CN^-$ ion which is a stronger nucleophile.

Assertion: is more reactive towards nucleophilic addition reaction than .

Reason: Reactivity of carbonyl group is due to electrophilic nature of carbonyl carbon.

→

Read the passage given below and answer the following questions:
Ethers are readily cleaved by HI or HBr at 373K to form an alcohol and an alkyl halide.
$\text{R}-\text{O}-\text{R}+\text{HX}\xrightarrow{373\text{K}}\text{R}-\text{X}+\text{R}-\text{OH}$
$\text{R}-\text{OH}+\text{HX}\xrightarrow{373\text{K}}\text{R}-\text{X}+\text{H}_2\text{O}$
Mixed ether, containing primary or secondary alkyl group, when heated with hydrogen halide, the lower alkyl group forms halide and higher will form an alcohol. Tertiary alkyl ether when heated with hydrogen halide gives tertiary alkyl halide.
The following questions are multiple choice questions. Choose the most appropriate answer:

Among the following ethers, which one will produce methyl alcohol on treatment with hot concentrated HI?

$\ \ \ \ \ \ \ \ \ \ \ \ \text{CH}_3\\\ \ \ \ \ \ \ \ \ \ \ \ \ \ |\\\text{CH}_3-\text{C}-\text{O}- \text{CH}_3\\\ \ \ \ \ \ \ \ \ \ \ \ \ \ |\\\ \ \ \ \ \ \ \ \ \ \ \ \ \text{CH}_3 $
$\text{CH}_3-\text{CH}-\text{CH}_2-\text{O}-\text{CH}_3\\\ \ \ \ \ \ \ \ \ \ \ \ \ |\\\ \ \ \ \ \ \ \ \ \ \ \text{CH}_3$
$\text{CH}_3-\text{CH}_2-\text{CH}_2-\text{CH}_2-\text{O}-\text{CH}_3$
$\text{CH}_3-\text{CH}_2-\text{CH}-\text{O}-\text{CH}_3\\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ |\\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{CH}_3$

When $CH_2 = CH - O - CH_2 - CH_3$ reacts with one mole of HI, one of the products formed is:

Ethane.
Ethanol.
Iodoethene.
Ethanal.

$(CH_3)_3COCH_3$ and $CH_3OC_2H_5$ are treated with hydroiodic acid. The fragments obtained after reactions are respectively:

$(CH_3)_3CI + CH_3OH; CH_3I + C_2H_5OH$
$(CH_3)_3CI + CH_3OH; CH_3OH + C_2H_5I$
$(CH_3)_3COH + CH_3I; CH_3OH + C_2H_5I$
$CH_3I + (CH_3)_3COH; CH_3I + C_2H_5OH$

Which of the following ether is unlikely to be cleaved by hot cone. HBr?

→

Read the passage given below and answer the following questions:
Nitric acid reacts with most of the metals (except noble metals like gold and platinum) and non-metals. Towards its reaction with metals. $HNO_3$ acts as an acid as well as an oxidising agent. Like other acids, $HNO_3$ liberate nascent hydrogen from metals which further reduces the nitric acid into number of products like $NO, NO_2, N_{2O}$ or $NH_3.$ The different stages of reduction of nitric acid are:
$\ \ _{+5}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ _{+4}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ _{+2}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ _{+1}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ _{-3}\\\text{HNO}_3\xrightarrow{\ \ \ \ +\text{e}\ \ \ \ }\text{NO}_2\xrightarrow{\ \ \ \ +2\text{e}^-}\text{NO}\xrightarrow[\text{NaOH}]{\ \ \ \ +\text{e}^-}\text{N}_2\text{O}\xrightarrow{\ \ \ \ +4\text{e}^-}\text{NH}_3$
The product of the reduction of $HNO_3$ depends upon the nature of the metal, concentration of nitric acid and temperature.
The following questions are multiple choice questions. Choose the most appropriate answer:

Which of the following reactions is used to prepare laughing gas?

$Pb +$ dil. $HNO_3 \rightarrow$
$Hg +$ dil. $HNO_3 \rightarrow$
$Zn +$ dil. $HNO_3 \rightarrow$
$Cu +$ dil. $HNO_3 \rightarrow$

Gold and platinum does not dissolve in $HNO_3$ but soluble in $1 : 3$ mixture of $HNO_3$ and $HCl$ due to the formation of respectively.

$Au(NO_3)_2, [Pt(NO_3)_2]$
$H[AuCl_4J, H_2[PtCl_6]$
$[AuCl_6]^{2-}, [PtCl_2)^{2-}$
$[Au(NO_3)_4], [Pt(NO_3)_6]^{2-}$

Identify B in the following reaction.

$\text{Cu}+\text{HNO}_{3{\text{(conc.)}}}\xrightarrow{\ \ \ \ }\ \ \ \ \ \ (\text{A})\ \ \ \ \ \ \ +\ \ \ \ \ \ \ (\text{B})+\text{H}_2\text{O}\\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ {\text{Deep blue colour}}\ \ \ \ \ \ \ \text{Gas}$

$NO_2$
$N_2$
$NO$
$N_2O$

In which of the following reactions $HNO_3$ will not act as an oxidising agent?

$HNO_3 + H_2SO_4 \rightarrow$
$HNO_3 + FeS0_4 + H_2S0_4 \rightarrow$
$KI + HNO_3 \rightarrow$
$Au + HNO_3\rightarrow$

When dil. $HNO_3$ reacts with Hg, which gas will liberate?

$N_2$
$O_2$
$NO$
$NO_2$

→

Read the passage given below and answer the following questions:
Aldehydes and ketones are reduced to primary and secondary alcohols respectively by $NaBH_4$ or $LiAlH_4$ as well as catalytic hydrogenation. The carbonyl group of aldehydes and ketones is reduced to

group on treatment with Zn-Hg and cone. HCl (Clemmensen reduction) or with hydrazine followed by NaOH or KOH in highly boiling solvent such as ethylene glycol (Wolff-Kishner reduction).Aldehydes differ from ketones in their oxidation reactions. Aldehydes are easily oxidised to carboxylic acids on treatment with $HNO_3, KMnO_4, K_2Cr_2O_7$ etc. Even mild oxidising agents mainlyTollens' reagent and Fehling's solution also oxidise aldehydes. Ketones are generally oxidised under vigorous conditions i.e., strong oxidising agents and at elevated temperatures, to give mixture of carboxylic acids having lesser number of C-atoms than the parent ketone.
The following questions are multiple choice questions. Choose the most appropriate answer:

Which of the following cannot be made by reduction of ketone or aldehyde with $NaBH_4$ in methanol?

1-Butanol
2-Butanol
2-Methyl-1-propanol
2-Methyl-2-propanol

The carbonyl compound producing an optically active product by reaction with $LiAlH_4$ is:

Propanone
Butanone
3-pentanone
Benzophenone

A substance $C_4H_{10}O (X)$ yields on oxidation a compound $C_4H_8O$ which gives an oxime and a positive iodoform test. The substance X on treatment with cone. $H_2SO_4$ gives $C_4H_8$. The structure of the compound (X) is:

$CH_3CH_2CH_2CH_2OH$
$CH_3CH(OH)CH_2CH_3$
$(CH_3)_3COH$
$CH_3CH_2- O - CH_2CH_3$

In the oxidation of by acidified $K_2Cr_2O_7$, the products are:

$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{O}\\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ ||\\\text{CH}_3-\ ^\text{14}\text{C}-\text{OH}$ and $\text{CH}_3\text{CH}_2\text{COOH}$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{O}\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ ||\\\text{CH}_3(\text{CH}_2)_2\text{COOH}-\text{C}-\text{OH}$ and $ \ \ \ \ \ \ \ 14\\\text{CH}_3\text{CH}_2\text{COOH}$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 14\\\text{CH}_3\text{CH}_2\text{CH}_2\text{COOH}+\text{HCOOH}$
None of these.

The appropriate reagent for the following transformation is:

$\text{Na}_2\text{NH}_2,^-\text{OH}$
$\text{NaBH}_4$
$\frac{\text{H}_2}{\text{Ni}}$
$\text{AICl}_3$

→

Read the passage given below and answer the following questions:
A chlorocompound $(A)$ on reduction with $Zn-Cu$ and ethanol gives the hydrocarbon $(B)$ with five carbon atoms. When $(A)$ is dissolved in dry ether and treated with sodium metal it gave $2, 2, 5, 5 -$ tetramethylhexane. The treatment of $(A)$ with alcoholic $KCN$ gives compound $( C).$
The following questions are multiple choice questions. Choose the most appropriate answer:

The compound $(A)$ is:

$1-$chloro$-2, 2-$dimethylpropane.
$1-$chloro$-2, 2-$dimethyl butane.
$1-$chloro$-2-$methyl butane.
$2-$chloro$-2-$methyl butane.

The reaction of $(C)$ with Na, $C_2H_5OH$ gives:

$(CH_3)_3C CH_2CONH_2$
$(CH_3)_3C NH_2$
$(CH_3)_3C CH_2CH_2NH_2$
$(CH_3)_2CHCH_2NH_2$

The reaction of $(C)$ with Na, $C_2H_5OH$ is called:

Gilman reaction.
Mendius reaction.
Grooves process.
Swart's reaction.

The reaction of $(A)$ with aq. $KOH$ will preferably favour:

$S_N1$ mechanism.
$S_N2$ mechanism.
$E_1$ mechanism.
$E_2$ mechanism.

Compound $(B)$ is:

$N-$pentane.
$2, 2-$dimethylpropane.
$2-$methylbutane.
None of these.

→

In these questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
Assertion: Colloidal particles show Brownian movement.
Reason: Brownian movement arises because of the impact of the molecules of the dispersion medium with the colloidal particles.

→

Amines are basic in nature. The $pK_b$ value is a measure of the basic strength of an amine. Lower the value of $pK_b$ more basic is the amine. The effect of substituent on the basic strength of amines in aqueous solution was determined using titrations. The substituent $"X"$ replaced $"-CH_2"$ group in piperidine $($ compound $1)$ and propylamine $CH_3CH_2CH_2NH_2, ($compound $2).$
Compound $1:$

Compound $2: HXCH_2CH_2NH_2$

(source: Hall Jr, $H. K. (1956).$ Field and inductive effects on the base strengths of amines. Journal of the American Chemical Society, $78(11), 2570-2572.) $
Study the above data and answer the following questions:
$a.$ Plot a graph between the electronegativity of the substituent vs $pK_b$ value of the corresponding substituted propyl amine $($ given that $pK_a + pK_b =14).$ Is there any relation between the electronegativity of the substituent and its basic strength?
$b.$ The electronegativity of the substituent $"C6H5CON\ "$ is $3.7,$ what is the expected pKa value of compound $C_6H_5CONHCH_2CH_2NH_2?$
$(i) \ 9.9 \ (ii) \ 9.5 \ (iii) \ 9.3 \ (iv) \ 9.1$
$c.$ The pKa value of the substituted piperidine formed with substituent $"X\ "$ is found to be $8.28.$ What is the expected electronegativity of $"X\ "$
$(i)\ 3.5 \ (ii)\ 3.4 \ (iii)\ 3.8\ (iv) \ 3.1$

→

The following reaction, $\text{A}_{(\text{g})}\xrightarrow{\ \ \triangle\ \ \ }\text{P}_{(\text{g})}+\text{Q}_{(\text{g})}+\text{R}_{(\text{g})},$ follows first order kinetics. The half-life period of this reaction is $69.3s$ at $500^\circ C$. The gas A is enclosed in a container at $500^\circ C$ and at a pressure of $0.4$ atm.
The following questions are multiple choice questions. Choose the most appropriate answer:

The rate constant for the reaction is:

$0.4s^{-1}$
$0.02s^{-1}$
$0.01s^{-1}$
$0.3s^{-1}$

The pressure of the gas $A$ after $230$ s will be:

$0.04$ atm
$0.36$ atm
$0.4$ atm
$0.036$ atm

The total pressure of the system after $230$ swill be:

$2.15$ atm
$1.12$ atm
$0.4$ atm
$3.08$ atm

The plot ofln[A] vs twill be:

Linear with slope $= k$
Linear with intercept $= In[A]_0$
Linear with slope $= In[A]_0$
Linear with intercept $= [A]_0$

Which of the following is not an example of first order reaction?

$\text{C}_2\text{H}_{4(\text{g})}+\text{H}_{2(\text{g})}\rightarrow\text{C}_2\text{H}_{6(\text{g})}$
$2\text{N}_2\text{O}_{5(\text{g})}\rightarrow4\text{NO}_{2(\text{g})}+\text{O}_{2(\text{g})}$
$2\text{N}\text{H}_{3(\text{g})}\xrightarrow[\triangle]{\text{pt}}\text{N}_{2(\text{g})}+3\text{H}_{2(\text{g})}$
$2\text{N}_2\text{O}_{(\text{g})}\xrightarrow{\ \ \triangle\ \ }2\text{N}_{2(\text{g})}+\text{O}_{2(\text{g})}$

→

Answer

Need a full question paper?

Explore more

Similar questions

Alcohols, Phenols, and Ethers — Chemistry STD 12 Science — Question

Answer

Need a full question paper?

Explore more

Similar questions