JEE Main 2025 Apr 4 Shift 2, Chemistry Q3: Properties and Important Reactions of Aldehydes & Ketones

The iodoform reaction (NaOI/NaOH) gives the yellow solid $CH{I}_3$ only with substrates carrying a $C{H}_3\text{-}CO\text{-}$ or $C{H}_3\text{-}CH(OH)\text{-}$ group attached to H or to a carbon.

(A) Butan-2-ol, $C{H}_{3}CH(OH)C_2{H}_5$: has the $C{H}_3\text{-}CH(OH)\text{-}$ motif. $✓$

(B) Propan-1-ol: no $C{H}_3\text{-}CH(OH)\text{-}$ group. $\times$

(C) Butan-2-one, $C{H}_3\text{-}CO\text{-}{C}_2{H}_5$: methyl ketone. $✓$

(D) Acetic acid: carboxylic acid, no methyl carbonyl reactive under haloform. $\times$

(E) Propanal: $C{H}_{3}C{H}_{2}CHO$, the methyl is not bound to the carbonyl carbon. $\times$

$\therefore$ Only (A) and (C) give the yellow iodoform precipitate.