Question

(a) What are the products obtained when methane reacts with chlorine in diffused sunlight?
(b) Write equations for the above reactions.
(c) Name and define the type of above reaction.

Answer 1

(a) In diffused sunlight, chlorination of methane takes place until all the the hydrogen atoms in methane are replaced by chlorine atoms. It results in a mixture of products composed of chloromethane, dichloromethane, trichloromethane (chloroform) and tetrachloromethane (carbon tetrachloride).

(b) The equations involved in chlorination are:

$$\begin{gathered} {\mathrm{CH}}_4+{\mathrm{Cl}}_2\to {\mathrm{CH}}_3\mathrm{Cl}+\mathrm{HCl} \\ {\mathrm{CH}}_3\mathrm{Cl}+{\mathrm{Cl}}_2\to {\mathrm{CH}}_2{\mathrm{Cl}}_2+\mathrm{HCl} \\ {\mathrm{CH}}_2{\mathrm{Cl}}_2+{\mathrm{Cl}}_2\to {\mathrm{CHCl}}_3+\mathrm{HCl} \\ {\mathrm{CHCl}}_3+\mathrm{HCl}\to {\mathrm{CCl}}_4+\mathrm{HCl} \end{gathered}$$

(c) The above reactions are substitution reactions. A reaction in which the hydrogen in the alkane molecule is replaced by another atom or group of atoms is called a substitution reaction.