Chapter 10, Problem 5PP

Interpretation Introduction

Interpretation:

The chain reaction mechanism for the formation of $1,1-\text{dichloroethane and }1,2-\text{dichloroethane}$ is to be written, when ethane is chlorinated.

Concept introduction:

Radical halogenation is the reaction in which hydrogen atoms of alkanes are replaced by chlorine atoms and results in the formation of alkyl halides, along with the formation of hydrogen halides as a by-product.

At normal temperature and pressure, chlorine and methane do not react with each other. The reaction is initiated by light or heat. When exposed to light, ${\text{Cl}}_2$ absorbs the wavelength of light, gets excited and initiates the reaction. However, when the temperature is raised above ${100}^{\circ }\text{C}$, the reaction starts.

The reaction that is initiated by light is more efficient because a very small amount of light photons allows a large number of products to be formed.