CBSE 2026 · Region 3 · Set 2 · Q24 · 3 marks

An organic compound (A) with molecular formula $\displaystyle \mathrm{C}_{3} \mathrm{H}_{5} \mathrm{~N}$ on reaction with $\displaystyle \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{MgBr}$ followed by hydrolysis, gives a compound (B). Compound

(B)

forms an orange-red precipitate with $\displaystyle 2,4$-DNP reagent and does not give iodoform test. It neither reduces Tollens' or Fehling's reagent nor does it decolourise bromine water. On drastic oxidation with chromic acid it gives a carboxylic acid (C) having molecular formula $\displaystyle \mathrm{C}_{7} \mathrm{H}_{6} \mathrm{O}_{2}$. Identify the compounds (A), (B) and (C). Write the reactions of compound (A) with $\displaystyle \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{MgBr}$ followed by hydrolysis to give compound (B).

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CBSE Class 12 Chemistry past-paper question from the 2026board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.