NEET Chemistry Haloalkanes and Haloarenes Questions Solved

When CH₃CH₂CHCl₂ is treated with NaNH₂, the product formed is

(a) CH₃-CH=CH₂ (b) CH₃-C $\equiv$ CH

#Physical & Chemical Properties

(b) CH₃-CH₂-CHCl₂ $\to_{∆}^{{NaNH}_{2} (sodamide)}$ CH₃-CH=CHCl $\to_{∆}^{{NaNH}_{2}}$ CH₃-C $\equiv$ CH

final product

Difficulty Level:

(a)
20%
(b)
38%
(c)
30%
(d)
14%

Chlorobenzene reacts with Mg in dry ether to give a compound (A) which further reacts with ethanol to yield

(a) phenol (b) benzene

Difficulty Level:

(a)
21%
(b)
42%
(c)
26%
(d)
13%

R-CH₂-CCl₂-R $\overset{Reagent}{\to}$ R-C $\equiv$ C-R. The reagent is

(a) Na (b) HCl in H₂O

#Physical & Chemical Properties

In presence of ethanolic KOH substrate gives an elimination reaction.

Difficulty Level:

(a)
19%
(b)
11%
(c)
56%
(d)
16%

Ethyl chloride is converted into diethyl ether by

(a) Wurtz reaction (b) Grignard reaction

(d) C₂H₅Cl - NaOC₂H₅ $\to$ C₂H₅-O-C₂H₅ + NaCl

It is an example of Williamson's synthesis. Limitations of Williamson's synthesis if 3 $°$ alkyl halide used in reaction then alkene formed.

Difficulty Level:

(a)
29%
(b)
11%
(c)
15%
(d)
48%

The alkyl halide is converted into an alcohol by

(a) addition (b) substitution

#Physical & Chemical Properties

(b) RCl + NaOH(aq) $\to$ ROH + NaCl

It is an example of nucleophilic substitution reaction.

Difficulty Level:

(a)
8%
(b)
68%
(c)
19%
(d)
7%

Addition of Br₂ on cis-butene-2 gives:

(a) a racemic mixture of 2,3-dibromobutane

(b) meso form of 2,3-dibromobutane

(d) laevo form of 2,3-dibromobutane

#Isomer and Chirality

(a) Follow mechanism of addition reaction.

Difficulty Level:

(a)
60%
(b)
30%
(c)
10%
(d)
3%

The number of different substitution products possible when ethane is allowed to react with bromine in sunlight are:

(a) 9 (b) 6

#Isomer and Chirality

(a) CH₃CH₂Cl; CH₃CHCl₂; CH₂ClCH₂Cl; CH₃CCl₃;CH₂ClCHCl₂; CH₂ClCCl₃; CHCl₂CHCl₂; CHCl₂CCl₃;

Difficulty Level:

(a)
23%
(b)
43%
(c)
17%
(d)
19%

CH3-CH2-C|H-CH3 Cl obtained by chlorination of n-butane, will be

(a) meso form (b) racemic mixture

#Mechanism of Substitution Reactions

(b) Chlorination of n-butane takes place by free radical mechanism as follows:

Difficulty Level:

(a)
21%
(b)
62%
(c)
12%
(d)
7%

In $S_{N^{2}}$ reactions, the correct order of reactivity for the following compounds : ${CH}_{3} Cl$ , ${CH}_{3} {CH}_{2} Cl$ , ${({CH}_{3})}_{2} CHCl$ and ${({CH}_{3})}_{3} CCl$ is :

(a) ${CH}_{3} Cl$ > ${({CH}_{3})}_{2} CHCl$ > ${CH}_{3} {CH}_{2} Cl$ > ${({CH}_{3})}_{3} CCl$

(b) ${CH}_{3} Cl$ > ${CH}_{3} {CH}_{2} Cl$ > ${({CH}_{3})}_{2} CHCl$ > ${({CH}_{3})}_{3} CCl$

(d) ${({CH}_{3})}_{2} CHCl$ > ${CH}_{3} {CH}_{2} Cl$ > ${CH}_{3} Cl$ > ${({CH}_{3})}_{3} CCl$

#Mechanism of Substitution Reactions

(b) Due to more -I.E. of attached groups in ${({CH}_{3})}_{3} CCl$ or due to max crowding round central carbon atom favours $S_{N}$ l mechanism.

Difficulty Level:

(a)
12%
(b)
74%
(c)
10%
(d)
5%

Action of RMgX with vinyl chloride gives:

(a) alkane (b) alkyne

Difficulty Level:

(a)
32%
(b)
13%
(c)
35%
(d)
22%