Discussion Forum



1)

The solubility  product of$ Ag_{2}CrO_{4}$ is $32 \times 10^{-12}$ . What is the concentration  of $CrO_{4}^{-}$ ions in that solution?


A) $2 \times 10^{-4}M$

B) $1.6 \times 10^{-4}M$

C) $8 \times 10^{-4}M$

D) $ 7 \times 10^{-8}M$

Answer:

Option A

Explanation:

$Ag_{2}CrO_{4} \rightarrow 2Ag^{+}+CrO_{4}^{2-}$

  S                                     2S               S

$K_{SP}=(2s)^{2}s=4s^{2}s=4s^{3}$

    $S=\left(\frac{K_{sp}}{4}\right)^{1/3}\Rightarrow\left(\frac{32\times10^{-12}}{4}\right)^{1/3}=2\times10^{-4}M$