Question

(i) Write the equation for the preparation of carbon tetrachloride from methane.
(ii) Draw the structural formula of ethyne.
(iii) How is the structure of alkynes different from that of alkenes?

Answer 1

(i) The equations for the preparation of carbon tetrachloride from methane are as follows:

$$\begin{gathered} \underset{\mathrm{Methane}}{{\mathrm{CH}}_4}+{\mathrm{Cl}}_2\underset{\mathrm{Diffused}\mathrm{sunlight}}{\overset{∆}{\to }}{\mathrm{CH}}_3\mathrm{Cl}+\mathrm{HCl} \\ {\mathrm{CH}}_3\mathrm{Cl}+{\mathrm{Cl}}_2\underset{\mathrm{Diffused}\mathrm{sunlight}}{\overset{∆}{\to }}{\mathrm{CH}}_2{\mathrm{Cl}}_2+\mathrm{HCl} \\ {\mathrm{CH}}_2{\mathrm{Cl}}_2+{\mathrm{Cl}}_2\underset{\mathrm{Diffused}\mathrm{sunlight}}{\overset{∆}{\to }}{\mathrm{CHCl}}_3+\mathrm{HCl} \\ {\mathrm{CHCl}}_3+{\mathrm{Cl}}_2\underset{\mathrm{Diffused}\mathrm{sunlight}}{\overset{∆}{\to }}\underset{\mathrm{Carbon}\mathrm{tetrachloride}}{{\mathrm{CCl}}_4}+\mathrm{HCl} \end{gathered}$$

(ii) The structural formula for ethyne is $\mathrm{HC}\equiv \mathrm{CH}$

(iii) Alkenes consist of double bonded carbon atoms, whereas alkynes consist of triple bonded carbon atoms.