50 mL of a sample of clear saturated solution of `Ag_(2)CrO_(4)` requies 20 mL of a `XM Pb(NO_(3))_(2)` for its titration. What is the value of X ? `(K_(SP)for Ag_(2)CrO_(4)=1.6xx10^(-12))`

Explanation

For `Ag_(2)CrO_(4)hArrunderset(2S)(2Ag^(+))+underset(S)(CrO_(4)^(2-))`
`K_(SP)=4S^(3)`
`:. S=3sqrt((K_(SP))/(4))=3sqrt((1.6xx10^(-12))/(4))`
`=0.736xx10^(-4)mol litre^(-1)`
`:. [CrO_(4)^(2-)]=0.736xx10^(-4)M`
`=0.736xx10^(-4)xx2N`
(N = Valence factor x M)
Also, Meq.of `Pb(NO_(3))_(2)= Meq.of CrO_(4)^(2-)`
`:. Xxx2xx20=0.736xx2xx10^(-4)xx50`
`X=1.84xx10^(-4)M`