Question

If the solubility product of CuS is \(6 × 10^{–16}\), calculate the maximum molarity of CuS in aqueous solution.

Answer 1

The correct answer is: \(2.45 \times 10^{-8} mol L^{-1}.\)
Solubility product of CuS, \(K_{sp} = 6 \times 10^{-16}\)
Lets be the solubility of CuS in \(mol L^{-1}.\)
\(CuS ↔Cu^{2+} + S^{2-}\)
                  \(  s \)          \( s\)
Now, \(K_{sp}=[Cu^{2+} ][S^{2-}]\)
\(=s \times s\)
\(= s^2\)
Then, we have, \(K_{sp} = s^2=6×10^{-16}\)
\(⇒s=\sqrt{6\times10^{-16}}\)
\(= 2.45 \times 10^{-8}mol L^{-1}\)
Hence, the maximum molarity of CuS in an aqueous solution is \(2.45 \times 10^{-8} mol L^{-1}.\)