Question

How is ethyne converted to

(iii) tetrabromoethane

Answer 1

Ethyne $\left({\mathrm{C}}_2{\mathrm{H}}_2\right)$ gives addition reaction with Hydrogen $\left({\mathrm{H}}_2\right)$ and halogens because the triple bond is highly reactive in nature.

Chemical reaction

The chemical reaction of Ethyne with Bromine $\left({\mathrm{Br}}_2\right)$ is given below:

$$\begin{gathered} \mathrm{H}-\mathrm{C}\equiv \mathrm{C}-\mathrm{H}+{\mathrm{Br}}_2\to \mathrm{BrCH}=\mathrm{CHBr} \\ \mathrm{Ethyne}\mathrm{Bromine}1,2-\mathrm{Dibromoethene} \\ \mathrm{BrCH}=\mathrm{CHBr}+{\mathrm{Br}}_2\to {\mathrm{Cl}}_2\mathrm{CH}-{\mathrm{CHCl}}_2 \\ 1,2-\mathrm{Dibromoethene}\mathrm{Bromine}1,1,2,2-\mathrm{Tetrabromoethane} \end{gathered}$$