See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

We analyze each reaction to determine which gas/product is released: (a) Benzoic acid with 14C-labeled carbonyl carbon + NaHCO3: The reaction of a carboxylic acid with NaHCO3 produces CO2. The CO2 originates from the bicarbonate (HCO3-), not from the carboxylic acid carbon. Since the label (14C) is on the carbonyl carbon of benzoic acid, the CO2 released comes from the unlabeled bicarbonate carbon. Therefore the gas evolved is regular (unlabeled) CO2 = (r). (b) Benzoic acid (unlabeled) + NaH14CO3 (bicarbonate with 14C label): Again, the CO2 evolved in the reaction of carboxylic acid + NaHCO3 comes from the bicarbonate carbon. Here the bicarbonate carbon is labeled (14C), so the gas evolved is 14CO2 = (q). (c) Benzoic acid + Na (sodium metal): Carboxylic acids react with active metals like Na to release H2 gas. PhCOOH + Na --> PhCOONa + 1/2 H2. Therefore the gas evolved is H2 = (s). (d) Benzenesulfonic acid + NaNH2 (sodium amide, a strong base): NaNH2 is the sodium salt of ammonia (NH3, pKa ~38). Benzenesulfonic acid is a strong acid. The stronger acid displaces the weaker acid: PhSO3H + NaNH2 --> PhSO3Na + NH3. Therefore the gas evolved is NH3 = (p). Summary: (a) -> (r): unlabeled CO2 (b) -> (q): 14CO2 (c) -> (s): H2 (d) -> (p): NH3 Therefore, the correct answer is {"a": ["r"], "b": ["q"], "c": ["s"], "d": ["p"]}.