See image — Amines Chemistry Question

💡 Solution & Explanation

Step 1 - Identify the starting material and reaction sequence. The starting amine is (CH3)2CHCH2N(CH2CH3)2, which is a tertiary amine: isobutyl group on nitrogen with two ethyl groups. Step 2 - Reaction with CH3I (methylation). The tertiary amine reacts with CH3I to form a quaternary ammonium iodide salt. The methyl group is added to nitrogen: (CH3)2CHCH2N+(CH3)(CH2CH3)2 I- This gives a quaternary ammonium salt with one isobutyl group, one methyl group, and two ethyl groups on nitrogen. Step 3 - Treatment with Ag2O/H2O (Hofmann elimination conditions). Ag2O/H2O converts the iodide salt to the quaternary ammonium hydroxide: (CH3)2CHCH2N+(CH3)(CH2CH3)2 OH- Step 4 - Heat (Hofmann elimination / Cope elimination). Hofmann elimination of quaternary ammonium hydroxides follows the Hofmann rule: elimination preferentially occurs from the least substituted beta-carbon (least hindered), forming the less substituted alkene. The beta-hydrogens available are: - From the two ethyl groups (CH2CH3): beta-H on CH3 of ethyl group → gives H2C=CH2 (ethylene, least substituted) - From the isobutyl group (CH2CH(CH3)2): beta-H on CH2 adjacent to N → gives isobutylene H2C=C(CH3)2 Hofmann elimination favors removal of proton from the least hindered beta-carbon. The ethyl groups provide less hindered beta-hydrogens (primary CH3), giving ethylene (H2C=CH2). The amine left behind after losing one ethyl group as ethylene is: (CH3)2CHCH2-N(CH3)(CH2CH3), i.e., (CH3)2CHCH2N(CH3)(CH2CH3) This matches option (c): (CH3)2CHCH2N(CH3)(CH2CH3) + H2C=CH2 Step 5 - Why other options fail. (a) Wrong: would require removal of all substituents and formation of primary amine, not consistent with one Hofmann elimination step. (b) Wrong: would require loss of the isobutyl group as isobutylene, which is disfavored under Hofmann conditions (more substituted alkene). (d) Wrong: this is just the intermediate quaternary ammonium salt before elimination, not the product after heating. Therefore, the correct answer is C.