JEE Advanced 2016 · Paper 1, Chemistry question 29

Tollens' reagent is reduced by aldehydes and by α-hydroxy ketones.

• (A) Acrolein, $\ce{CH2=CH-CHO}$: an aldehyde. Positive.
• (B) Benzaldehyde: an aldehyde. Positive.
• (C) Benzoin, $\ce{PhCH(OH)COPh}$: an α-hydroxy ketone, oxidised (via its enediol) to benzil. Positive.
• (D) Chalcone, $\ce{PhCH=CHCOPh}$: an α,β-unsaturated ketone with no aldehyde or α-hydroxyl. Negative.

(A), (B), (C)