Ninhydrin is a test for amino acids. Egg albumin, which contains proteins (polymers of amino acids), gives a positive test with ninhydrin due to the reaction with amino groups.
\( \text{M} \xrightarrow{\text{CH}_3\text{MgBr}} \text{N} + \text{CH}_4 \uparrow \xrightarrow{\text{H}^+} \text{CH}_3\text{COCH}_2\text{COCH}_3 \)