MHTCET 13 Apr 2026 Shift 1 Paper

Concept:Ketones react with hydrazine ($\mathrm{NH}_{2}-\mathrm{NH}_{2}$) to form hydrazones through a condensation reaction.Explanation:The reagent $\mathrm{NH}_{2}-\mathrm{NH}_{2}$ is known as hydrazine.It contains two amino groups linked directly to each other.When a ketone reacts with hydrazine, a condensation reaction occurs.The oxygen atom of the carbonyl group ($\mathrm{C}=\mathrm{O}$) is replaced by the group $=\mathrm{N}-\mathrm{NH}_{2}$.Water ($\mathrm{H}_{2}\mathrm{O}$) is eliminated as a by-product.This reaction is called condensation because a small molecule like water is lost.The general equation for the reaction is:$$\mathrm{R}_{2}\mathrm{C}=\mathrm{O} + \mathrm{NH}_{2}-\mathrm{NH}_{2} \rightarrow \mathrm{R}_{2}\mathrm{C}=\mathrm{N}-\mathrm{NH}_{2} + \mathrm{H}_{2}\mathrm{O}$$The product formed is $\mathrm{R}_{2}\mathrm{C}=\mathrm{N}-\mathrm{NH}_{2}$, which is called a hydrazone.A phenyl hydrazone would be formed only if phenylhydrazine ($\mathrm{C}_{6}\mathrm{H}_{5}\mathrm{NHNH}_{2}$) were used instead of hydrazine.Aniline and anisole are unrelated aromatic compounds and are not formed in this reaction.Answer:Option B: Hydrazone