Test: Preparation Of Alkyl Halides


19 Questions MCQ Test Chemistry Class 12 | Test: Preparation Of Alkyl Halides


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This mock test of Test: Preparation Of Alkyl Halides for Class 12 helps you for every Class 12 entrance exam. This contains 19 Multiple Choice Questions for Class 12 Test: Preparation Of Alkyl Halides (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Preparation Of Alkyl Halides quiz give you a good mix of easy questions and tough questions. Class 12 students definitely take this Test: Preparation Of Alkyl Halides exercise for a better result in the exam. You can find other Test: Preparation Of Alkyl Halides extra questions, long questions & short questions for Class 12 on EduRev as well by searching above.
*Multiple options can be correct
QUESTION: 1

Only One Option Correct Type

Direction (Q. Nos. 1-7) This section contains 7 multiple choice questions. Each question has four choices (a), (b), (c) and (d), out of which ONLY ONE option is correct.

Q. When (S)-2-bromopentane is brominated, several 2,3-dibromopentane are formed, which of the following is not formed?

Solution:

Correct Answer : b,c

Explanation : During bromination of (S)-2-bromopentane, the configuration at second carbon is not affected. It remains R configuration. The configuration at third carbon atom can be either S or R. In options B and C, the configuration at the second carbon atom is R. Hence, they cannot be formed.

QUESTION: 2

The yield of alkyl bromide obtained as a result of heating the dry silver salt of carboxylic acid with bromine in CCI4 is

Solution:

The reaction follows free radical mechanism and alkyl free radical is formed in the propagation step as



Hence, stability of alkyl free radical (3° > 2° > 1°) determine the reactivity.

QUESTION: 3

Which is incorrect about Hunsdiecker's reaction ?

Solution:

Except F2, almost all halogens react with RCOOAg giving alkyl halide via Hunsdiecker reaction. With l2 if RCOOAg is in excess, R— I formed in first step reacts further with unreacted salt to give ester as 
R — COOAg+ R — I → R — COOR + AgI

QUESTION: 4

The major product of the following reaction is 

Solution:

Free radical bromination occur. Preferably at highest degree carbon where most stable free radical is formed.

QUESTION: 5

Racemic mixture is obtained due to the halogenation of

Solution:

If free radical halogenation generate a chiral carbon, racemic mixture of halides are always formed due to equal probability of halogenation from both sides of planar free radical.


QUESTION: 6

The reaction of SOCI2 on alkanols to form alkyl chlorides gives good yields because

Solution:


The gaseous byproducts escape out on its own continuously driving the reaction in forward direction.

QUESTION: 7

Addition of bromine on propene in the presence of brine yields a mixture of

Solution:



Nucleophilic attack in step-ll occur at the carbon atom which can better accommodate the positive charge. Hence, attack of Br- or Cl- in second step occur at 2° carbon rather that at 1° carbon.

*Multiple options can be correct
QUESTION: 8

One or More than One Options Correct Type

Direction (Q. Nos. 8-12) This section contains 5 multiple choice questions. Each question has four choices (a), (b), (c) and (d), out of which ONE or MORE THAN ONE are correct.

Q. Which of the following reagents can bring about free radical chlorination of propane?

Solution:

Both SO2CI2 and Cl2 undergo homolytic bond fission when heated or irradiated with light.

*Multiple options can be correct
QUESTION: 9

In which of the following reaction(s), the major product is a primary alkyl bromide?

Solution:




*Multiple options can be correct
QUESTION: 10

Consider the following reaction,

Q. 

The expected product(s) is/are

Solution:

NBS in CCI4 brings about allylic brom ination by free radical mechanism:





*Multiple options can be correct
QUESTION: 11

Consider the following reaction,

Q.

When a pure enantiomer of X is taken in the above reaction, correct completion regarding the reaction is/are

Solution:


*Multiple options can be correct
QUESTION: 12

Choose the correct statement(s) from the following regarding free radical chlorination and bromination reaction of alkane.

Solution:

In free radical halogenation of alkane, the first step of propagation is exothermic when Cl2 is used while it is endothermic when Br2 is used. Also chlorination occur at very fast rate, hence very less selective while bromination occur at very slow rate, occurs selectively where most stable free radical is formed.

QUESTION: 13

Comprehension Type

Direction (Q. Nos. 13-15) This section contains a paragraph, describing theory, experiments, data, etc.
Three questions related to the paragraph have been given. Each question has only one correct answer among the four given options (a), (b), (c) and (d).

Passage

An alcohol (R — OH) can be converted into alkyl chloride by the treatm ent with HCI. Reaction involves protonation of alcohol followed by the formation of carbocation intermediate. Carbocation intermediate in the final step undergo nucleophilic attack by Cl- ion as :

Q. 

Which of the following alcohol reacts most easily?

Solution:

As mentioned in mechanism, reaction proceed via carbocation intermediate. Hence, alcohol forming most stable carbocation reacts most easily. Alcohol (c) forms aromatic (highly stable) carbocation, hence most reactive.

QUESTION: 14

An alcohol (R — OH) can be converted into alkyl chloride by the treatm ent with HCI. Reaction involves protonation of alcohol followed by the formation of carbocation intermediate. Carbocation intermediate in the final step undergo nucleophilic attack by Cl- ion as :

Q. 

Which of the following can catalyse the above reaction? 

Solution:

ZnCI2 is a Lewis acid, helps in the form ation of carbocation intermediate, hence catalyse the reaction.

QUESTION: 15

An alcohol (R — OH) can be converted into alkyl chloride by the treatm ent with HCI. Reaction involves protonation of alcohol followed by the formation of carbocation intermediate. Carbocation intermediate in the final step undergo nucleophilic attack by Cl- ion as :

Q. 

What is the correct order of reactivty of the followings with HCl? 

 

      

 

    

Solution:

The order of stability of carbocation intermediates formed follows the order of reactivity.

*Answer can only contain numeric values
QUESTION: 16

One Integer Value Correct Type

Direction (Q, Nos. 16-19) This section contains 4 questions. When worked out will result in an integer from 0 to 9 (both inclusive).

Q. 

If 2,4-dimethyl pentane is subjected to free radical chlorination reaction, how many different monochlorinated products would be formed?


Solution:

*Answer can only contain numeric values
QUESTION: 17

On free radical chlorination reaction of butane, how many different, optically active, dichloroalkanes would be formed ?


Solution:




Only three pairs of enantiomers are formed.

*Answer can only contain numeric values
QUESTION: 18

If 1, 3-butadiene is treated with excess of bromine in CCI4 , how many different tetrabromides would be formed?


Solution:

*Answer can only contain numeric values
QUESTION: 19

Consider the following reaction,

Q. 

How many different monobromo derivatives would be produced?


Solution:


(I) has two optically active enantiomers and (II) has two geometrical isomers.

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