## Chemistry and Chemical Reactivity (9th Edition)

$[Au^+] = 4.5 \times 10^{-7}M$
1. Write the $K_{sp}$ expression: $AuCl(s) \lt -- \gt 1Au^{+}(aq) + 1Cl^-(aq)$ $2 \times 10^{-13} = [Au^{+}]^ 1[Cl^-]^ 1$ 2. Considering a pure solution: $[Au^{+}] = 1S$ and $[Cl^-] = 1S$ $2 \times 10^{-13}= ( 1S)^ 1 \times ( 1S)^ 1$ $2 \times 10^{-13} = S^ 2$ $\sqrt [ 2] {2 \times 10^{-13}} = S$ $4.5 \times 10^{-7} = S$ - This is the molar solubility value for this salt. Molar solubility $[Au^+] = 1S = 4.5 \times 10^{-7}M$