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Test: Reaction Mechanism Level - 4

30 Questions MCQ Test Organic Chemistry | Test: Reaction Mechanism Level - 4

Description

Attempt Test: Reaction Mechanism Level - 4 | 30 questions in 60 minutes | Mock test for Chemistry preparation | Free important questions MCQ to study Organic Chemistry for Chemistry Exam | Download free PDF with solutions

QUESTION: 1

For the reaction below if the concentration of KCN is increased four times, the rate of the reaction will be:

A.
Doubled
B.
Increased four times
C.
Unaffected
D.
Halved

Solution:

This is an SN1 reaction, so, rate of the reaction only depends on substrate, it doesn't depend on nucleophile. Hence change in concentration of the nucleophile won't affect the rate.

C is correct.

QUESTION: 2

The major product formed in the reaction of 1, 3-butadiene with bromine is at high temperature:

Solution:

When 1,3-butadiene reacts with Br2 at high temperature (heating) then 1,4- addition to diene takes place, so mainly 1,4-dibromobut-2-ene is formed. But at low-temperature 1,2-addition dominates and 3,4-dibromobut-1-ene is major product

QUESTION: 3

The products formed in the following reaction is:

Solution:

QUESTION: 4

In the reaction sequence

The product (Y) is:

Solution:

QUESTION: 5

The major product of the reaction

Solution:

According to Markovnikov's rule, when an alkene undergoes hydrohalogenation, the proton is added to the carbon with the highest number of hydrogens, resulting in a stable carbocation intermediate before the nucleophile attack.

QUESTION: 6

The major product formed in the following reaction.

Solution:

QUESTION: 7

The major product formed in the following reaction.

Solution:

QUESTION: 8

The major product obtained in the following reaction

Solution:

QUESTION: 9

The major product formed in the following reaction is:

Solution:

QUESTION: 10

Choose the correct order of reactivity for dehydration of the given alcohols using concentrated sulfuric acid.

A.
2-methylpropan – 2-ol > 2- butanol > 1-butanol
B.
2-methylpropan – 2-ol > 1- butanol > 2-butanol
C.
2- butanol > 2 - methylpropan – 2-ol > 1-butanol
D.
1-butanol > 2-butanol > 2-methylpropan – 2-ol.

Solution:

QUESTION: 11

Electrophilic nitrations of the following compounds follow the trend:

A.
S > R > P > Q
B.
R > S > P > Q
C.
R >P > S > Q
D.
P > S > R > Q

Solution:

QUESTION: 12

Elimination reactions of compounds 1 and 2 with sodium ethoxide give two alkenes, A and B, but with different selectivities. Which of the following statements best indicates the most probable outcome?

A.
A both from 1and 2
B.
B from 1 and A from 2
C.
A from 1 and B from 2
D.
B both from 1 and 2

Solution:

QUESTION: 13

What would be the final major product of the following chemical reaction if it is carried out twice, one at 5 C^o and the second time at 45 C⁰?

Solution:

A is correct, as at higher temperature condensation takes place and removal of water takes place, thus formation of alkene at high temperature only.

QUESTION: 14

What is the major product if HBr (in excess) is added to H₂C = CH – CH₂ – OH

A.
CH₃ – CH (Br) – CH₂ – Br
B.
H₂C = CH – CH₂ – Br
C.
CH₃ – CH (Br) – CH₂ – OH
D.
CH₃– CH (OH) – CH₂ – OH

Solution:

QUESTION: 15

The reaction of sodium ethoxide with ethyl iodide to form diethyl ether is termed

A.
Electrophilic substitution
B.
Nucleophilic substitution
C.
Electrophilic addition
D.
Radical substitution

Solution:

QUESTION: 16

What is the final product after the following reaction has gone to completion?

A.
Benzene
B.
Benzenehexachloride
C.
Chlorobenzene
D.
Dichlorobenzene

Solution:

QUESTION: 17

The major product formed in the following reaction is:

A.
B.
C.
50:50 mixture of above two compounds
D.

Solution:

QUESTION: 18

Among the bromides I-III given below, the order of their reactivity in the S_N1 reaction is:

A.
III > II > I
B.
II > III > I
C.
III > I > II
D.
II > I > III

Solution:

QUESTION: 19

The major product formed in the reaction benzoic acid with isobutylene in the presence of a catalytic amount of sulfuric acid is:

Solution:

First of all COOH group is deactivating group, so there will be no ring substitution. Now, in cat. amount of H2SO4, isobutylene gives 3 dgree carbocation. Then lone pair of O of acid will attack it and gives the product (C).

QUESTION: 20

Among the following compounds, the one that undergoes deprotonation most readily in the presence of a base, to form a carbanion is:

Solution:

QUESTION: 21

Regarding the saponification of M and N shown below, the correct statement is that

A.
M reacts factor than N because the transition state is less crowded for M than for N.
B.
M reacts slower than N because the transition state is more crowded for M than for N
C.
N and M react at the same rate because of formation of tetrahedral intermediate in both
D.
N reacts slower than M because of its greater thermodynamics stability.

Solution:

The mechanism for the base promoted hydrolysis reaction begins with the nucleophilic hydroxide reacting with the electrophilic carbonyl carbon atom to form the tetrahedral intermediate.