An aqueous solution of a salt X turns blood red on treatment with S C N - and blue on treatment with K 4 F e C N 6 , X also gives a positive chromyl chloride test. The salt X is:

Step-by-step solution

FeCl 3 + 3 SCN aq - ⇌ Fe SCN 3 + 3 Cl - Blood red 4 FeCl 3 + 3 K 4 Fe CN 6 → 1 2 KCl + Fe 4 Fe CN 6 Prussian blue 2 FeCl 3 + 3 H 2 SO 4 → Fe 2 SO 4 3 + 6 HCl K 2 Cr 2 O 7 + 2 H 2 SO 4 → 2 KHSO 4 + 2 CrO 3 + H 2 O CrO 3 + 2 HCl → CrO 2 Cl 2 + H 2 O Chromyl chloride CrO 2 Cl 2 +4NaOH → Na 2 CrO 4 Yellow +2NaCl+2H 2 O Na 2 CrO 4 + Pb CH 3 COO 2 → PbCrO 4 + 2 CH 3 COONa Yellow ppt.