Which of the following reagents can be used to distinguish between an aldehyde and a ketone?

Tollens’ reagent is a solution containing silver ions that tests for aldehydes. Aldehydes reduce the silver ions to metallic silver, creating a shiny silver mirror on the test tube.

Ketones do not react with Tollens’ reagent, so no silver mirror forms. This difference allows chemists to identify whether a compound is an aldehyde or ketone.

The test works because aldehydes are easily oxidized while ketones resist oxidation. The silver mirror test is a simple visual way to distinguish these two functional groups.