See image — Haloalkanes and Haloarenes Chemistry Question

💡 Solution & Explanation

Concept: KCN and AgCN react differently with alkyl halides due to the ambident nature of the cyanide ion (CN-), which can attack through either carbon (C-attack, giving nitrile) or nitrogen (N-attack, giving isonitrile/isocyanide). Step 1: Reaction of R-Cl with KCN. KCN is an ionic cyanide salt. The cyanide ion (CN-) acts as a nucleophile and attacks through carbon (softer end), forming R-CN (alkyl cyanide / nitrile). Upon reduction with LiAlH4, R-CN gives R-CH2-NH2, a primary amine. Step 2: Reaction of R-Cl with AgCN. AgCN is a covalent silver cyanide. The nitrogen end attacks the alkyl halide (N-attack), forming R-NC (alkyl isocyanide / isonitrile). Upon reduction with LiAlH4, R-NC gives R-NH-CH3 (a secondary amine, specifically N-methylamine derivative) — more precisely, R-NC reduces to R-NHCH3, i.e., an isonitrile reduces to a secondary amine R-NH-CH3. Wait, correcting: LiAlH4 reduction of R-NC (isocyanide) gives R-NH-CH3 (secondary amine). LiAlH4 reduction of R-CN (nitrile) gives R-CH2-NH2 (primary amine). Step 3: Compare Products A and B. Product A: R-CH2-NH2 (primary amine) Product B: R-NHCH3 (secondary amine, where the N-methyl comes from reduction of the isocyanide carbon) Both A and B have the same molecular formula (same number of carbons, hydrogens, nitrogens) since R-CN and R-NC are isomers, and their LiAlH4 reduction products R-CH2-NH2 and R-NHCH3 are also isomers with the same molecular formula. Step 4: Determine the type of isomerism. R-CH2-NH2 is a primary amine (RCH2NH2) and R-NHCH3 is a secondary amine. They have the same molecular formula but different functional group arrangements (primary amine vs secondary amine). This is functional group isomerism (functional isomerism). Why other options fail: - Chain isomers: same carbon skeleton arrangement is required to differ; here the issue is functional group type, not chain branching. - Position isomers: same functional group at different positions; here the functional groups themselves differ (primary vs secondary amine). - Metamers: metamers are isomers differing in alkyl groups on either side of the same functional group (e.g., ethers or secondary amines). Both A and B are not the same class of amine, so they are not metamers of each other. Therefore, the correct answer is C.