MHTCET 13 Apr 2026 Shift 2 Paper

Concept:The iodoform test is given by compounds containing the methyl ketone group $-\mathrm{COCH}_{3}$ or alcohols that can be oxidised to such a group.Explanation:A compound gives iodoform if it has $-\mathrm{COCH}_{3}$ or if it can be oxidised to form that group.Ethyl methyl ketone is $\mathrm{CH}_{3}\mathrm{COCH}_{2}\mathrm{CH}_{3}$, which contains $-\mathrm{COCH}_{3}$, so it forms iodoform.Isopropyl alcohol is $\mathrm{CH}_{3}\mathrm{CH}(\mathrm{OH})\mathrm{CH}_{3}$, which oxidises to acetone, $\mathrm{CH}_{3}\mathrm{COCH}_{3}$, so it forms iodoform.3-Methyl-2-butanone is $\mathrm{CH}_{3}\mathrm{COCH}(\mathrm{CH}_{3})_{2}$, which also contains $-\mathrm{COCH}_{3}$, so it forms iodoform.Isobutyl alcohol is $(\mathrm{CH}_{3})_{2}\mathrm{CHCH}_{2}\mathrm{OH}$, a primary alcohol without the $\mathrm{CH}_{3}\mathrm{CH}(\mathrm{OH})-$ group.Its oxidation does not produce a methyl ketone, so it cannot form iodoform.Answer:Option D: Isobutyl alcohol