Aldehydes, Ketones and Carboxylic Acids

Concept:Each reaction in List-I undergoes a characteristic organic transformation to give a major product, which is matched with the correct structure in List-II.Explanation:Reaction P is ozonolysis ($\mathrm{O}_3$, then $\mathrm{Zn/H}_2\mathrm{O}$) of an alkene, which cleaves the double bond to give carbonyl compounds (aldehyde or ketone).Reaction Q is oxidation with alkaline $\mathrm{KMnO}_4$ (cold, dilute) that adds two hydroxyl groups across the double bond, forming a vicinal diol.Reaction R is catalytic hydrogenation ($\mathrm{H}_2/\mathrm{Pd}$) that reduces an alkene to the corresponding alkane.Reaction S uses sodium in liquid ammonia ($\mathrm{Na/NH}_3\mathrm{(l)}$) to reduce an alkyne to a trans-alkene.By comparing the product structures from List-II (not shown here), the correct assignments are: P gives structure 1, Q gives structure 2, R gives structure 3, and S gives structure 4.Answer:Option C: P $\rightarrow$ 1; Q $\rightarrow$ 2; R $\rightarrow$ 3; S $\rightarrow$ 4.