Compound P ( C ₉ H ₁₀ O ) forms a silver mirror with Tollens' reagent but does not undergo Aldol condensation. On vigorous oxidation with acidic KMnO ₄ , it yields benzene-1,4-dicarboxylic acid. The compound P is :

Step-by-step solution

A positive Tollens' test indicates that compound P is an aldehyde. Since P does not undergo Aldol condensation, it must lack -hydrogens. This implies the - CHO group is directly attached to the benzene ring. Vigorous oxidation with acidic KMnO ₄ yields benzene-1,4-dicarboxylic acid (terephthalic acid), which indicates that P is a para-disubstituted benzene derivative. Subtracting the benzene ring ( C ₆ H ₄ ) and the aldehyde group ( - CHO ) from the molecular formula C ₉ H ₁₀ O leaves an ethyl group ( - C ₂ H ₅ ).