Question

Consider the reactions :-
Identify $A,X,Y$ and $Z$

• A. A-Methoxymethane, X-Ethanol, Y-Ethanoic acid, Z-Semicarbazide
• B. A - Ethanal , X - Ethanol , Y - But - 2 - enal , Z - Semicarbazone
• C. A- Ethanol, X- Acet aldehyde, Y- Butanone, Z- Hydrazone
• D. A-Methoxymethane, X-Ethanoic acid, Y-Acetate ion, Z-hydrazine

Answer 1

Answer: (B)

Since 'A' gives positive silver mirror test therefore, it must be an aldehyde or $\alpha$

Hydroxyketone.

Reaction with semicarbazide indicates that A can be an aldehyde or ketone.

Reaction with $O{H}^{-}$ i.e., aldol condensation (by assuming alkali to be dilute) indicates that $A$ is aldehyde as aldol reaction of ketones is reversible and carried out in special apparatus.

These indicates option (2).

$\underset{(X)}{C{H}_3-C{H}_{2}OH}\underset{573K}{\overset{Cu}{\to }}\underset{(A)}{C{H}_3-CHO}\underset{\Delta }{\overset{(Ag(N{H}_3{)}_2{)}^{+},O{H}^{-}}{\to }}C{H}_3-COOH$