When liquid $A$ is treated with a freshly prepared ammoniacal silver nitrate solution,it gives a bright silver mirror. The liquid forms a white crystalline solid on treatment with sodium hydrogensulphite. Liquid $B$ also forms a white crystalline solid with sodium hydrogensulphite but it does not give a test with ammoniacal silver nitrate. Which of the two liquids is an aldehyde? Write the chemical equations of these reactions also.

(A) Since liquid $A$ reduces ammoniacal silver nitrate (Tollen's reagent),$A$ is an aldehyde.
Reaction with sodium hydrogensulphite:
$R-C(=O)-R' + NaHSO_3 \rightleftharpoons R-C(OH)(SO_3Na)-R'$
(Where $R$ or $R'$ is $H$ for aldehyde,and both are alkyl/aryl for ketone. This forms a white crystalline solid.)
Tollen's test for aldehyde $(A)$:
$RCHO + 2[Ag(NH_3)_2]^+ + 3OH^- \rightarrow RCOO^- + 2Ag(s) + 4NH_3 + 2H_2O$
(The formation of silver mirror confirms the presence of an aldehyde.)
Conclusion: Liquid $A$ is an aldehyde,while liquid $B$ is a ketone.