how can differentiate between aldehyde and ketone - Science - Carbon and its Compounds

Question

how can differentiate between aldehyde and ketone

Shukla Paladhi · Accepted Answer

Dear user,
Aldehydes and ketones can be
differentiated as under

Test

Aldehydes

Ketones

Tollen’s reagent
test

+ve
Aldehydes reduce
Tollens’ reagent to form shiny silver mirror

-ve
Ketones do not reduce
Tollens’ reagent and hence, there is no formation of shiny
silver mirror

Fehling’s solution
test

+ve
Aldehydes reduce
Fehling’s solution to form red precipitates of cuprous
oxide

-ve
Ketones do not reduce
Fehling’s solution and hence, there is no of red precipitate
formation

Schiff’s reagent
test

+ve
Aldehydes restore the pink
colour of Schiff’s reagent

-ve
Ketones do not restore the
pink colour of Schiff’s reagent

Reduction with
LiAlH4

Aldehydes get reduced to
primary alcohols in presence of LiAlH4

Ketones get reduced to
secondary alcohols in presence of LiAlH4

Hope, this answers your
question
Cheers!!

Test	Aldehydes	Ketones
Tollen’s reagent test	+ve Aldehydes reduce Tollens’ reagent to form shiny silver mirror.	-ve Ketones do not reduce Tollens’ reagent and hence, there is no formation of shiny silver mirror.
Fehling’s solution test	+ve Aldehydes reduce Fehling’s solution to form red precipitates of cuprous oxide.	-ve Ketones do not reduce Fehling’s solution and hence, there is no of red precipitate formation.
Schiff’s reagent test	+ve Aldehydes restore the pink colour of Schiff’s reagent.	-ve Ketones do not restore the pink colour of Schiff’s reagent.
Reduction with LiAlH₄	Aldehydes get reduced to primary alcohols in presence of LiAlH₄.	Ketones get reduced to secondary alcohols in presence of LiAlH₄.