Both aldehydes and ketones contain the carbonyl group (>C=O). The carbonyl group can be confirmed by:
- 2,4-dinitrophenyl hydrazine (2,4-DNP test)
- Sodium bisulphite
2, 4 - DNP Test
The organic compound is treated with 2,4-DNP reagent and warmed over a water bath. Formation of yellow or orange crystals indicate the presence of a carbonyl group (aldehydic or ketonic).
Sodium Bisulphite Test
The organic compound is treated with a saturated solution of soduim bisulphite. The mixture is shaken well and left for 15 minutes. The formation of a crystalline precipitate indicates the presence of a carbonyl group.