MCQ
The solubility product of $AB_2$ is $8\times 10^{-5}\,M^3$ . If the salt is $80\,\%$ dissociated in saturated solution, find the solubility of the salt.

Given [Molar mass $(AB_2) = 360$ ]

  • A
    $0.050$
  • B
    $0.065$
  • C
    $0.034$
  • $0.074$

Answer

Correct option: D.
$0.074$
d
$A{B_2}\overset {80\% } \longleftrightarrow \mathop {{A^{ + 2}}}\limits_{0.8S}  + \mathop {2{B^ - }}\limits_{2 \times 0.8S} $

${{\text{K}}_{{\text{sp}}}} = (0.8 \times {\text{S}}){(2 \times 0.8{\text{S}})^2}$

$8 \times {10^{ - 5}} = 2.048{{\text{S}}^3}\left( { = 2{{\text{S}}^3}} \right)$

${{\text{S}}^3} = \frac{{8 \times {{10}^{ - 5}}}}{2}$

${{\text{S}}^3} = 40 \times {10^{ - 6}}$

$S = \sqrt[3]{{40 \times {{10}^{ - 6}}}}$

$ = 3.4 \times {10^{ - 2}}\,{\text{M}}$

$ = 0.034\,{\text{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