X,Y and Z are three organic compounds. All the three undergo iodoform test .Only Y and Z can react with 2,4 -DNP. Only Z can reduce tollen's reagent. Here X,Y and Z respectively
CH3CH2OH, CH3COCH3, CH3CHO
Z is aldehyde; Y is ketone ; X, Y, Z contains CH3 - CHOH - (or) CH3 - CO - group