What `[H^(+)]` must be maintained in a saturated `H_(2)S(0.1)M` to precipitate `CdS` but not `ZnS` if `[Cd^(2+)]=[Zn^(2+)]=0.1` initially?

(x)/(20)M concentration of H^(+) ion must be maintained in a saturate H_(2)S(0.1M) to precipitates CdS but not ZnZ, if [Cd^(2+)]=[Zn^(2+)]=0.1M initially. K_(sp)(CdS)=8xx10^(-27), K_(sp)(ZnS)=1xx10^(-21)K_(a)(H_(2)S)=1xx10^(-21)ZnS will not precipitate at concentration of H^(+) greater than (x)/(20)M . The value of x is .

What (H_(3)O^(+)) must be maintained in a saturated H_(2)S solution to precipitate Pb^(2+) , but not Zn^(2+) from a solution in which each ion is present at a concetration of 0.01 M ? (K_(SP) for H_(2)S= 1.1xx10^(-22), K_(SP) for ZnS=1.0xx10^(-21))

What (H_(3)O^(+)) must be maintained in a saturated H_(2)S solution to precipitate Pb^(2+) , but not Zn^(2+) from a solution in which each ion is present at a concetration of 0.01 M ? (K_(SP) for H_(2)S= 1.1xx10^(-22), K_(SP) for ZnS=1.0xx10^(-21))

What is the minimum pH required to prevent the precipitation of Zn^(+2) in a solution that is 0.05 M ZnCl_(2) and saturated with 0.2M H_(2)S (Given : K_(sp) ( ZnS) = 10^(-20) and Ka_(1) xx Ka_(2) of H_(2)S = 10^(-20) )

An acidified of 0.05 M Zn^(2+) is saturated with 0.1 M H_2S . What is the minimum molar concentration (M) or H^+ required to prevent the precipitation of ZnS ? Use K_(sp)(ZnS) = 1.25 xx10^(-22) and overall dissociation constant of H_2S, K_("NET") =K_1K_2=1xx10^(-21) .