KVPY2020Chemistryd and f Block Elements
When a mixture of NaCl , K 2 Cr 2 O 7 and conc. H 2 SO 4 is heated in a dry test tube, a red vapor X is evolved. This vapor X turns an aqueous solution of NaOH yellow due to the formation of Y .   X and Y , respectively, are:
Options
- ACrCl 3 and Na 2 Cr 2 O 7
- BCrCl 3 and Na 2 CrO 4
- CCrO 2 Cl 2 and Na 2 CrO 4
- DCr 2 SO 4 3 and Na 2 Cr 2 O 7
Correct answer
C. CrO 2 Cl 2 and Na 2 CrO 4
Step-by-step solution
4 NaCl + K 2 Cr 2 O 7 + 6 H 2 SO 4 → 4 NaHSO 4 + 2 KHSO 4 + 2 CrO 2 Cl 2 ( X ) + 6 H 2 O CrO 2 Cl 2 + 4 NaOH ⟶ Na 2 CrO 4 ( Y ) + 2 NaCl + 2 H 2 O X = CrO 2 Cl 2 Y = Na 2 CrO 4