p-Amino-N,N-dimethylaniline is added to a strongly acidic solution of X. The resulting solution is treated with a few drops of aqueous solution of Y ot yield blue coloration due to the formation of methylene blue. Treatment of the aqueous solution of Y with the reagent potassium hexacyanoferrrate (II) lead to the formation of an intense blue precipitate . The precipitate dissolves on excess addition of the reagent. Similarly , treatment of the solution of Y with the solution of potassium hexacynoferrate(III) leads to a brown coloration due to the formation of Z.
The compound Z is