Question

A saturated solution of $NiC{O}_3$ was evaporated to dryness. A 250.0 mL sample was found to contain $1.1\times {10}^{-2}g$ $NiC{O}_3$. The molar mass of $NiC{O}_3$ is 118.7 g mol. The molar solubility of $NiC{O}_3$ is :

• A. $9.3\times {10}^{-5}M$
• B. $3.7\times {10}^{-4}M$
• C. $4.4\times {10}^{-2}M$
• D. $1.4\times {10}^{-7}M$

Answer 1

Answer: (B)

$3.7\times {10}^{-4}M$

250.0 mL of sample contains $1.1\times {10}^{-2}g$ of $NiC{O}_3$.

$1L$ of sample will contain $\frac{1000}{250}\times 1.1\times {10}^{-2}g=4.4\times {10}^{-2}g$ of $NiC{O}_3$.

The molar mass of $NiC{O}_3$ is 118.7 g/mol.

The molar solubility of $NiC{O}_3$ is $\frac{4.4\times {10}^{-2}g}{118.7g/mol/L}=3.7\times {10}^{-4}M$