Chapter 10, Problem 4PP

Interpretation Introduction

Interpretation: Step-wise synthesis of ${\text{CCl}}_4$ with maximum yield is to be explained.

Concept introduction:

Radical halogenation is a substitution reaction in which hydrogen atoms of alkanes are replaced by halogen atoms resulting in the formation of alkyl halides. Also hydrogen halides are formed as a by-product.

One problem with alkane halogenations is that multiple substitutions occur unless an excess of alkane is used.

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

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