Question

Explain Tollen’s reagent test. 

OR 

Explain silver mirror test.

Answer 1

• Tollen’s reagent is an (ammoniacal silver nitrate) [Ag(NH₃)₂]⁺ OH^-.
• When an aldehyde, like acetaldehyde is heated with Tollen’s reagent, it is oxidised to acetic acid and silver ions Ag⁺ in Tollen’s reagent complex are reduced to silver Ag giving greyish black precipitate or deposition of silver on inner surface of the test tube which shines like a mirror. Hence this test is also called silver mirror test.
• This test is not given by ketones.
• Hence Tollen’s reagent is used to distinguish between aldehydes and ketones.