The molar solubility of $\mathrm{CaF}_2$ $\left(\mathrm{K}_{\mathrm{sp}}=5.3 \times 10^{-11}\right)$ in $0.1 \mathrm{M}$ solution of $\mathrm{NaF}$ will be

• A

  $5.3 \times 10^{11} \mathrm{~mol} \mathrm{~L}^{-1}$
• B

  $5.3 \times 10^{-8} \mathrm{~mol} \mathrm{~L}^{-1}$
• Correct answer
  C

  $5.3 \times 10^{-9} \mathrm{~mol} \mathrm{~L}^{-1}$
• D

  $5.3 \times 10^{-10} \mathrm{~mol} \mathrm{~L}^{-1}$

Solution

Let the solubility of $\mathrm{CaF}_2$ in $0.1 \mathrm{M} \mathrm{NaF}$ is ' $\mathrm{S}$ ' $\mathrm{mol} \mathrm{L}^{-1}$

Hence, the correct answer is option: 'C'.