MHT CET Chemistry Question (2026) — Solution

Step-by-step solution

The iodoform test is given by compounds containing a methyl ketone group (CH_3-CO-) or a secondary alcohol group with a terminal methyl (CH_3-CH(OH)-), which gets oxidized to a methyl ketone by the reagent. Acetaldehyde (CH_3-CHO) contains a CH_3-CO- group and gives a positive test. Propan-2-ol (CH_3-CH(OH)-CH_3) contains a CH_3-CH(OH)- group and gives a positive test. Propanone (CH_3-CO-CH_3) contains a CH_3-CO- group and gives a positive test. Pentan-3-one (CH_3-CH_2-CO-CH_2-CH_3) does not contain a CH_3-CO- group. Therefore, it does not respond positively to the iodoform test. Answer: Pentan-3-one