During oxidation of unsymmetrical ketones the point of cleavage is such that keto group stays preferentially with the smaller alkyl group popoff ‟ s rule ).
[ Fehling solution is a mixture of Fehling solution A and Fehling solution B in 1 : 1 ratio . Fehling solution A is aqueous copper sulphate and Fehling solution B is alkaline sodium potassium tartrate which is also called , Rochelle salt .]
( c ) Benedict solution With it , aldehydes ( except benzaldehyde ) also give red ppt . of CU2O .
( d ) Schiff ’ s reagent It is an aqueous solution of magenta or pink coloured rosaniline hydrochloride which has been decolourised by passing
SO2 , Aldehydes give pink colour with this reagent but ketones do not .
Haloform reaction Aldehydes and ketones having at east one methyl group [ 3-α hydrogen ] linked to the carbonyl carbon atom ( methyl ketones ) are oxidised by sodium hypohalite to sodium salts of corresponding carboxylic acids having one carbon atom less than that of carbonyl compound . The methyl group is converted to haloform .