JEE Main202125 Feb 2021Morning ShiftChemistryIonic EquilibriumActual
The solubility of AgCN in a buffer solution of pH = 3 is x . The value of x is: [Assume : No cyano complex is formed ; K sp AgCN = 2 . 2 × 10 - 16 and K a HCN = 6 . 2 × 10 - 10 ]
Options
- A1 . 9 × 10 - 5
- B2 . 2 × 10 - 16
- C0 . 625 × 10 - 6
- D1 . 6 × 10 - 6
Correct answer
A. 1 . 9 × 10 - 5
Step-by-step solution
Let, the solubility be x Given that, K sp AgCN = 2 . 2 × 10 - 16 and K a HCN = 6 . 2 × 10 - 10 AgCN ⇌ Ag + x + CN - x    K sp = 2 . 2 × 10 - 16 H + + CN - ⇌ HCN    K = 1   K a = 1 6 . 2 × 10 - 10 K sp × 1   K a = Ag + CN - × [ HCN ] H + CN - 2 . 2 × 10 - 16 × 1 6 . 2 × 10 - 10 = [ S ] [ S ] 10 - 3 S 2 = 2 . 2 6 . 2 × 10 - 9 S 2 = 3 . 55 × 10 - 10 S = 3 . 55 × 10 - 10 S = 1 . 88 × 10 - 5 ⇒ 1 . 9 × 10