An unknown aldehyde A on reaction with alkali gives a `beta`- hydroxy aldehyd, which loses water to form an unsaturated aldehyde, But-2-enal. Another aldehyde 'B' disproporationation reaction in the presence of conc, alkali to form products C and D. C is an aryl alcohol wit the formula (`C_(2)H_(8))`
(1) Identify A and B.
(ii) Write the sequence of reactions involved.
(iii) Name the product, when B reacts with Zn amalgam and hydrochloric acid.

Explanation

(1) Aldehyde compound A on reacting with alkali gives a `beta`-hydroxy aldehyde which loses water to form unsaturated aldehyde but-2-enal. This is Aldol condensation reaction.
(2) The aldehyde compound B undergo disproportionation reacton with conc. alkali. This is Cannizzaro.s reaction.
(3) Product C is an aryl alcohol with formula `C_(7)H_(8)O`. It must be and is formed by condensation of benzaldehyde. Thus