Question

Give a simple chemical test to distinguish between propanal and propanone.

Hint:

Tollen's test is a reliable way to differentiate between aldehydes (which are oxidized) and ketones (which are not).

Answer 1

A simple test to distinguish between propanal (an aldehyde) and propanone (a ketone) is the Tollen's test. Propanal will give a silver mirror when treated with Tollen's reagent (ammoniacal silver nitrate solution), whereas propanone will not give this result. This is because aldehydes can be oxidized to carboxylic acids, whereas ketones are generally resistant to oxidation.