Identify A and B in the reaction given below:

$\text{Ethane}\text{nitrile}\underset{\text{aq}{\text{.H}}_{\text{2}}{\text{SO}}_{\text{4}}}{\overset{\text{Hydrolysis}}{\to }}\text{A}\underset{\text{Sodalime}}{\overset{\text{Decarboxylation}}{\to }}$

Alkyl cyanides are generally named as nitriles of acids which they produce on hydrolysis. The ending ic acid of common name of the acid is replaced by term nitrile and the letter 'O' is inserted in between. For example:

$\underset{\text{Acetonitrile}}{{\text{CH}}_{\text{3}}-\text{CN}}\stackrel{{\text{(H}}_{\text{2}}\text{O)}}{\to }\underset{\text{Acetic}\text{acid}}{{\text{CH}}_{\text{3}}\text{COOH}}$

So, the compound $\text{(A)}$ is Ethanoic acid.

$\underset{\text{Sodium}\text{acetate}}{{\text{CH}}_{\text{3}}\text{COOH}}\text{+}\underset{\text{Sodium}\text{Hydroxide}}{\text{NaOH}}\underset{\text{CaO}}{\overset{\text{Δ}}{\to }}\underset{\text{Methane}}{{\text{CH}}_{\text{4}}}\text{+}\underset{\text{Sodium}\text{carbonate}}{{\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}}$

So, the compound $\text{(B)}$ is Methane.