CLEAPSS Supporting practical science and technology
PP012 - Testing for carbonyl compounds with Tollen's reagent
Although both aldehydes and ketones contain the carbonyl functional group (-C=O), only aldehydes (or reducing sugars) give a positive ‘silver mirror’ test result with Tollen’s reagent. This small-scale test is a useful qualitative analysis technique for detecting the presence of aldehydes (or reducing sugars).