KCET2010Chemistryd and f Block Elements
A white crystalline salt A reacts with dilute HCl to liberate a suffocating gas B and also forms a yellow precipitate. The gas B turns potassium dichromate acidified with dilute H ₂ SO ₄ to a green coloured solution C. A, B and C are respectively
Options
- ANa ₂ SO ₃, SO ₂, Cr ₂ ( SO ₄ )₃
- BNa ₂ ~S ₂ O ₃, SO ₂, Cr ₂ ( SO ₄ )₃
- CNa ₂ ~S ₂ SO ₂, Cr ₂ ( SO ₄ )₃
- DNa ₂ SO ₄, SO ₂, Cr ₂ ( SO ₄ )₃
Correct answer
B. Na ₂ ~S ₂ O ₃, SO ₂, Cr ₂ ( SO ₄ )₃
Step-by-step solution
Gas B turns the colour of acidified K ₂ Cr ₂ O ₇ green thus it is SO ₂ and SO ₂ is obtained along with yellow precipitate when thio sulphate is treated with dilute acids. Thus, A is Na ₂ ~S ₂ O ₃ , B is SO ₂ and C is Cr ₂ ( SO ₄ )₃ . The reactions are as follows