Class 12 NEET Chemistry Aldehydes, Ketones And Carboxylic Acids Part 1

ammoniacal silver nitrate and used for the detection of -CHO group. Aldehydes reduce Tollens' reagent and itself gets oxidised to convert Ag+ ions to Ag powder which forms the silver coloured mirror in the test tube. So this test is also known as silver mirror test.
R−CHO+[Ag(NH3)2]+ →R−COO−+Ag