Propanal and propanone can be distinguished by any of the following tests:

1.Tollen's test: Propanal is an aldehyde. So, it reduces Tollen's reagent whereas, propanone being a ketone does not reduces Tollen's reagent, hence only propanal gives positive silver mirror test.

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2. Fehling's test: Aldehydes respond to Fehling's test, but ketones do not. Propanal being an aldehyde reduces Fehling's solution to a red-brown precipitate of , but propanone being a ketone does not.

Propanal

3. lodoform test: Aldehydes and ketones having at least one methyl group linked to the carbonyl carbon atom responds to iodoform test. They are oxidised by sodium hypoiodite (NaOI) to give iodoforms. Propanone being a methyl ketone responds to this test, but propanal does not.