7.68 The solubility product constant of Ag2CrO4 and AgBr are 1.1 × 10–12 and
5.0 × 10
–13 respectively. Calculate the ratio of the molarities of their saturated solutions.

Let s be the solubility of Ag2CrO4.
Then, AggCrO4Ag2++2CrO4-
Ksp=(2s)2.s=4s3
1.1×10-10=4s
s=6.5×10-5 M
Let s' be the solubility of AgBr.
AgBr(s)Ag++Br-
Ksp=S'2=5.0×10-13
s'=7.07×10-7 M
Therefore, the ratio of the molarities of their saturated solution is
2s'=6.5×10-5 M 7.07×10-7 M=91.9.