Hydrocarbons Question 279

Question: Which of the following is not formed by the reaction of $ Cl_2 $ on $ CH_4 $ in sunlight [AIIMS 1987]

Options:

A) $ CHCl_3 $

B) $ CH_3Cl $

C) $ CH_3CH_3 $

D) $ CH_3CH_2CH_3 $

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Answer:

Correct Answer: D

Solution:

$ CH_4\xrightarrow{Cl_2}CH_3Cl\xrightarrow{Cl_2}CH_2Cl_2\xrightarrow{Cl_2} $

$ CHCl_3\xrightarrow{Cl_2}CCl_4 $ .

Since this reaction takes place by free radical mechanism.

Hence, there is a possibility of formation of ethane.

$ \underset{\text{Methyl free radicals}}{\mathop{\overset{.}{\mathop{C}}H_3+\overset{.}{\mathop{C}}H_3}}\to \underset{Ethane}{\mathop{CH_3-CH_3}} $

$ CH_4\xrightarrow{Cl_2}CH_3Cl\xrightarrow{Cl_2}CH_2Cl_2\xrightarrow{Cl_2} $

$ CHCl_3\xrightarrow{Cl_2}CCl_4 $ .

Since this reaction takes place by free radical mechanism.

Hence, there is a possibility of formation of ethane.

$ \underset{\text{Methyl free radicals}}{\mathop{\overset{.}{\mathop{C}}H_3+\overset{.}{\mathop{C}}H_3}}\to \underset{Ethane}{\mathop{CH_3-CH_3}} $