lodoform test can be used to distinguish between:

Explanation

The iodoform test relies on the reaction of a compound with excess iodine and sodium hydroxide to form iodoform (CHI₃), a yellow crystalline solid with a distinctive smell. This reaction occurs with compounds containing a methyl ketone group (RCOCH₃) or a secondary alcohol group (RCH(OH)CH₃) adjacent to a α-hydrogen atom (hydrogen atom attached to the carbon next to the carbonyl or hydroxyl group).Therefore, the iodoform test can be used to distinguish between:(a) Ethanol and methanol: Ethanol (CH₃CH₂OH) gives a positive test due to the presence of a secondary alcohol group (CH₂CH(OH)), while methanol (CH₃OH) lacks the required α-hydrogen and gives a negative test.(b) Acetaldehyde (CH₃CHO) and methanal (CH₂O): Acetaldehyde gives a positive test due to the methyl ketone group (CH₃CO), while methanal lacks both the methyl ketone and α-hydrogen, leading to a negative test.(c) Acetone (CH₃COCH₃) and diethyl ketone (CH₃CH₂COCH₂CH₃): Acetone shows a positive test due to the presence of two methyl ketone groups.