Tollens’ test, also known as silver-mirror test, is a qualitative laboratory test used to distinguish between an aldehyde and a ketone. it exploits the fact that aldehydes are readily oxidized (see oxidation),
whereas ketones are not.
tollens’ test uses a reagent known as tollens’ reagent,
which is a colorless,
basic,
aqueous solution containing silver ions coordinated to ammonia [ag(nh3)2+].
it is prepared using a two-step procedure.