How will you distinguish between :
`CH_(3)CHO` (acetaldehyde or propanal) and `CH_(3)COCH_(3)` (acetone or propanaone).

Explanation

Distinguish between acetaldehyde (or propanal) and propanone (or Acetone). Acetaldehyde can be distinguished from propanone by the following two tests :
(a) Tollen.s reagent test. Acetaldehyde will reduce Tollen.s reagent to silver. When acetaldehyde is warmed with Tollen.s reagent, silver mirror is deposited on the walls of the test tube.
`underset("Acetaldehyde")(CH_(3)CHO) + underset("Tollen.s reagent")(2[Ag(NH_(3))_(2)]^(+)) + 2OH^(-) rarr underset("Amm. acetate")(CH_(3)COONH_(4)) + underset("SIlver mirror")(2Ag) + H_(2)O + 3NH_(3)`
Propanone will not give this test.
(b) Fehling soluton test. Acetaldehyde will reduce Fehling solution to cuprous oxide. When acetaldehyde is warmed with Fehling solution, a red precipitate of cuprous oxide is formed.
`underset("Acetaldehyde")(CH_(3)CHO) + underset("Fehling solution")([2Cu^(2+) + 5OH^(-)]) rarr CH_(3)CObar(O) + 3H_(2)O + underset("Red p pt.")(Cu_(2)O)`
Propanone will not give this test.