(d) Write short note on silver mirror.
Answers
Explanation:
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
Silver mirror test is used to distinguish aldehdyes from ketones. Aldehdyes give positive silver mirror test. Ketones do not give this test. In thist test, Tollen's reagent is used which is ammoniacal silver nitrate solution. It acts as mild oxidising agent and oxidizes aldehyde to acetate ion. Silver ion is reduced to metallic silver. This forms a bright silver mirror on the inner side of the container or it forms grayish black precipitate.
R−CHO+2[Ag(NH
3
)
2
]
+
+3OH
−
Δ
R−COO
−
+2Ag↓+2H
2
O+4NH
3