Question

The final product obtained when methane reacts with chlorine in the presence of sunlight is

• A. $C_2{Cl}_6$
• B. ${CCl}_4$
• C. ${CHCl}_3$
• D. ${CH}_2{Cl}_2$

Answer 1

The correct option is B

${\mathrm{CCl}}_4$

Explanation for correct option:

(B) ${\mathrm{CCl}}_4$

Substitution reaction

• Substitution reaction refers to the chemical reaction in which one or more hydrogen atoms in a hydrocarbon are replaced by another atom.
• In the presence of most reagents, saturated hydrocarbons are relatively unreactive and inert. Chlorine, on the other hand, rapidly reacts with hydrocarbons in the presence of sunlight.
• Chlorine$\left({\mathrm{Cl}}_2\right)$ undergoes a substitution reaction with methane$\left({\mathrm{CH}}_4\right)$ in the presence of sunlight. Chorine atoms can replace the hydrogen atoms one by one in the given reaction.
• It is a substitution reaction because one type of atom takes the place of another atom.
• Carbon tetrachloride$\left({\mathrm{CCl}}_4\right)$ is the final product obtained when methane reacts with chlorine in presence of the sunlight.

• The reaction is as follows:-

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

Thus, one can conclude that ${\mathrm{CCl}}_4$ is the final product obtained when methane reacts with chlorine in presence of the sunlight.

Explanation for incorrect options:

(A) ${\mathrm{C}}_2{\mathrm{Cl}}_6$ is not the final product obtained when methane reacts with chlorine in presence of the sunlight.

(C) ${\mathrm{CHCl}}_3$ is the intermediate product when methane reacts with chlorine in presence of the sunlight.

(D) ${\mathrm{CH}}_2{\mathrm{Cl}}_2$ is the intermediate product when methane reacts with chlorine in presence of the sunlight.

Hence, option (B) is correct. ${\mathrm{CCl}}_4$ is the final product obtained when methane reacts with chlorine in presence of the sunlight.