Question

The solubility of a sparingly soluble salt $A\left(OH\right)_{2}$ (mol. wt. 192.3) is $19.23 \, g/litre$ at $300 \, K$ . The $pH$ of its saturated solution assuming 80% ionisation at $300 \, K$ is :

• A. $1.0970$
• B. $12.9030$
• C. $13.2041$
• D. $12.0000$

Answer 1

Answer: (C)

$\text{S} = \frac{\text{19.23}}{\text{192.3}} \text{mol/litre} = \text{0.1 M}$

$∴ \, \, \left[\text{OH}^{-}\right] = \frac{\text{0.1} \times 2 \times 8 0}{1 0 0} = \text{0.16}$
$∴ \, \, \text{pOH} = \text{0.7958}$
$∴ \, \, \text{pH} = \text{13.2041}$