100 mL of 0.020 M AgNO3 is mixed with 100 mL of 0.010 M K2CrO4. These amounts are exactly stoichiometric for Ag2CrO4 (K_sp = 1.1 x 10^-12). The equilibrium [Ag^+] in the final solution (in mol L^-1) is

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$100 mL$ of $0.020 M$ $AgNO X_{3}$ is mixed with $100 mL$ of $0.010 M$ $K X_{2} CrO X_{4}$ . These amounts are exactly stoichiometric for $Ag X_{2} CrO X_{4}$ ( $K_{s p} = 1.1 \times 1 0^{- 12}$ ). The equilibrium $[Ag X^{+}]$ in the final solution (in $mol L^{- 1}$ ) is

Mixing gives

2.0

mmol

Ag X^{+}

and

1.0

mmol

CrO X_{4} X^{2 -}

, which precipitate completely as

Ag X_{2} CrO X_{4}

. The solid then dissolves to its saturation value: the solution contains only dissolved

Ag X_{2} CrO X_{4}

, so

s = (K_{s p} /4)^{1/3} = 6.5 \times 1 0^{- 5} M

and

[Ag X^{+}] = 2 s = 1.3 \times 1 0^{- 4} M