MCQ
$PbCl_2$ has max. concentration of $1.0\times10^{-3}\, M$ in its saturated aq. solution at $25\,^oC$. Its solubility in $0.1\, M\, NaCl$ solution will be
  • $4\times10^{-7}\, M$
  • B
    $4\times10^{-9}\, M$
  • C
    $2\times10^{-7}\, M$
  • D
    $2\times10^{-9}\, M$

Answer

Correct option: A.
$4\times10^{-7}\, M$
a
$\mathrm{PbCl}_{2}(\mathrm{s}) \rightleftharpoons \mathrm{Pb}^{2+}(\mathrm{aq})+2 \mathrm{Cl}^{-}(\mathrm{aq})$

$\therefore \quad \mathrm{K}_{\mathrm{sp}}=4 s^{3} \Rightarrow 4 \times\left(10^{-3}\right)^{3}=4 \times 10^{-9}$

Now in $\mathrm{NaCl}$ solution.

$\mathrm{K}_{\mathrm{sp}}\left(\mathrm{PbCl}_{2}\right)=\left[\mathrm{Pb}^{2+}\right]\left[\mathrm{Cl}^{-}\right]^{2}$

$\Rightarrow 4 \times 10^{-9}=s \times(0.1)^{2}$

$\Rightarrow \mathrm{s}=4 \times 10^{-7} \,\mathrm{M}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free