Question

The solubility of Ag2CO3 in water at 250C is 1 × 10-4 mole/litre. What is its solubility in 0.01 M Na2CO3 solution? Assume no hydrolysis of CO32- ion.

• A. 6 × 10-6 mole/litre
• B. 4 × 10-5 mole/litre
• C. 10-5 mole /litre
• D. 2 × 10-5 mole/litre

Answer 1

Answer: (C)

10-5 mole /litre

Answer 2

Na2CO3 $\rightleftharpoons$ 2Na+ + CO32–

2 × 0.01 0.01

Ag2CO3 $\rightleftharpoons$ 2 Ag+ + CO32–

2 x (x + 0.01) $\approx$ 0.01 Ksp = 4x2 (0.01)

Ksp = 4s3 = 4 × 10–12 = 4x2 (0.01)

$\Rightarrow$ x = 10–5