Nucleophilic substitution products from 1-bromopropane

Steps:

• Reaction 1 with NH₃ in ethanol forms the ammonium salt CH₃CH₂CH₂NH₃⁺ Br⁻ as compound X, since NH₃ initially substitutes Br⁻ to give the protonated amine.
• Reaction 2 produces Y, which hydrolyses to butanoic acid (CH₃CH₂CH₂COOH), so Y is butanenitrile (CH₃CH₂CH₂CN) via CN⁻ addition, extending the chain by one carbon.
• Reagents for Y: Aqueous KCN (or NaCN) enables SN2 substitution to form the nitrile without alcohol solvent interference.
• Choice B matches X as CH₃CH₂CH₂NH₃⁺ and reaction 2 reagents as KCN [Naq].

Why B is correct:

• Ammonia reaction yields the ammonium ion per the substitution mechanism: RBr + NH₃ → RNH₃⁺ Br⁻; aqueous KCN forms RCN, which hydrolyses to RCOOH + NH₃.

Why the others are wrong:

• A: X is free amine (not salt); KCN/EtOH works but doesn't match X.
• C: X is alcohol (wrong product; needs OH⁻, not NH₃); HCN/Naq is ineffective for substitution.
• D: X is alcohol (incorrect for NH₃ reaction); KCN/EtOH makes nitrile but mismatches X.

Final answer: B