See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

Step 1: Identify gas A. PhCOOH (benzoic acid) reacts with NaHCO3. Carboxylic acids react with NaHCO3 to release CO2 gas. PhCOOH + NaHCO3 -> PhCOONa + H2O + CO2 Gas A = CO2, molecular mass = 44. Step 2: Identify gas B. Ph-C≡CH (phenylacetylene) reacts with Na metal. Terminal alkynes are acidic enough to react with Na to release H2 gas. Ph-C≡CH + Na -> Ph-C≡C-Na + 1/2 H2 Gas B = H2, molecular mass = 2. Step 3: Identify gas C. Ph-OH (phenol) reacts with NaNH2 (sodium amide, a very strong base). NaNH2 deprotonates phenol to give NH3 gas. Ph-OH + NaNH2 -> Ph-ONa + NH3 Gas C = NH3, molecular mass = 17. Step 4: Identify gas D. R-OH (an alcohol) reacts with NaH (sodium hydride, a strong base/hydride). NaH deprotonates the alcohol to release H2 gas. R-OH + NaH -> R-ONa + H2 Gas D = H2, molecular mass = 2. Step 5: Sum the molecular masses. A + B + C + D = 44 + 2 + 17 + 2 = 65. Therefore, the correct answer is 65.