Answer
The minimun chloride ion concentration for precipitation to occur is equal to $1.8\times 10^{-5}M$
Work Step by Step
1. Write the $K_{sp}$ expression:
$ AgCl(s) \lt -- \gt 1Ag^{+}(aq) + 1Cl^{-}(aq)$
$1.8 \times 10^{-10} = [Ag^{+}]^ 1[Cl^{-}]^ 1$
$1.8 \times 10^{-10} = (1 \times 10^{-5})^ 1( 1S)^ 1$
2. Find the Chloride ion concentration.
$1.8 \times 10^{-10}= 1 \times 10^{-5} \times ( 1S)^ 1$
$ \frac{1.8 \times 10^{-10}}{1 \times 10^{-5}} = ( 1S)^ 1$
$1.8 \times 10^{-5} = S$
