As the compound (X) is giving a positive Hoffmann bromamide reaction, the compound (X) contains the CONH2 group. As only three carbons present, the structure of compound (X) is:
(X) → CH3CH2CONH2
Hoffmann bromamide reaction give 1° amine with one carbon less, therefore, the structure for compound (Y) is:
(Y) → CH3CH2NH2
The reaction involved are: