Question

State the method of preparation of ethanol :
(a) by hydrolysis of ethene,
(b) by hydrolysis of ethyl bromide.

Answer 1

(a) By hydrolysis of ethene: When concentrated sulphuric acid is added to ethene at a temperature of ${80}^{o}C$ and pressure of 30 atm, ethyl hydrogen sulphate is produced. Ethyl hydrogen sulphate on hydrolysis with boiling water gives ethanol.

$C_2{H}_4+H_{2}S{O}_4\stackrel{{80}^{o}C/30atm}{\to }{C}_2{H}_{6}S{O}_4$

$C_2{H}_{6}S{O}_4+H_{2}O⟶C_2{H}_5-OH+H_{2}S{O}_4$

(b) By hydrolysis of alkyl halide: Alcohols can be prepared by the hydrolysis of an alkyl halide with a hot dilute alkali.

$C_2{H}_{5}Cl+KOH\stackrel{boil}{\to }{C}_2{H}_5-OH+KCl$