Question

In the free radical chlorination, the two factors which determine the product ratio of various monochlorination products are the type of H being substituted and the number of a specific type of H being substituted. If activation energy for H-abstraction by chlorine radical is considered to be zero, what would be the percentage of l-chlorobutane amongthe monochlorobutanes obtained on free radical chlorination of butane?

• A. 6%
• B. 10%
• C. 40%
• D. 60%

Answer 1

Answer: (D)

60%

In the free radical chlorination, the two factors which determine the product ratio of various monochlorination products are the type of H being substituted and the number of a specific type of H being substituted. If activation energy for H-abstraction by chlorine radical is considered to be zero, the percentage of l-chlorobutane among the monochlorobutanes obtained on free radical chlorination of butane will be 60%.
Since, the activation energy for H-abstraction is considered to be zero, abstraction of all hydrogen will become equally likely.
The percentage of l-chlorobutane will depend on the probabilistic ratio. 6H of one type and 4H of other types will be abstracted.