2,4−DNP test is useful for the identification of carbonyl compounds.
The 2,4-dinitrophenylhydrazine can be used as a process for the identification of aldehydes and ketones.
The formed 2,4-dinitrophenylhydrazone is a solid that is purified and the melting point is determined. The comparison of a melting point with a table of known values could identify the compound as aldehyde or ketone