Give an example of the preparation of an alkane from an alkyl halide.

Alkyl halides (except fluorides) on reduction with zinc and dilute hydrochloric acid give alkanes.
$R-X + H_2 \xrightarrow{Zn + H^+} R-H + HX$
Example of reaction:
$(i)$ $CH_3Cl + H_2 \xrightarrow{Zn + H^+} CH_4 + HCl$
Chloromethane $\rightarrow$ Methane
$(ii)$ $CH_3CH_2Cl + H_2 \xrightarrow{Zn + H^+} CH_3CH_3 + HCl$
Chloroethane $\rightarrow$ Ethane
$(iii)$ $CH_3CH_2CH_2Cl + H_2 \xrightarrow{Zn + H^+} CH_3CH_2CH_3 + HCl$
$1$-Chloropropane $\rightarrow$ Propane
$(iv)$ $CH_3CH_2Br + H_2 \xrightarrow{Zn + H^+} CH_3CH_3 + HBr$
Bromoethane $\rightarrow$ Ethane
$(v)$ $CH_3CH(Br)CH_2CH_3 + H_2 \xrightarrow{Zn + H^+} CH_3CH_2CH_2CH_3 + HBr$
$2$-Bromobutane $\rightarrow$ Butane