Question

why ketone never gives fehling's test whereas fructose gives fehling's test..??

Answer 1

The compound to be tested is added to the Fehling'ssolution and the mixture is heated. Aldehydes are oxidized, giving a positive result, but ketones do not react, unless they are alpha-hydroxy-ketones. ...Fehling's can be used to screen for glucose in urine, thus detecting diabetes.