The values of `K_(sp)` of two sparingly soluble salts `Ni(OH)_(2)` and `AgCN` are `2.0xx10^(-15)` and `6xx10^(-17)` respectively. Which salt is more soluble ? Explain .

Explanation

`AgCN hArr Ag^(+)+CN^(-)`
`K_(sp)=[Ag^(+)][CN^(-)]=6xx10^(-17)`
`Ni(OH)_(2) hArr Ni^(2)+2OH^(-)`
`K_(sp)=[Ni^(2+)][OH^(-)]^(2)=2xx10^(-15)`
Let `[Ag^(+)]=S_(1),` then `[CN^(-)]=S_(1)`
Let `[Ni^(2+)]=S_(2)` then `[OH^(-)]=2S_(2)`
`S_(1)^(2)=6xx10^(-17)=S_(1)=7.8xx10^(-9)`
`(S_(2))(2S_(2))^(2)=2xx10^(-15), S_(2)=0.58xx10^(-4)`
`Ni(OH)_(2)` is more soluable than `AgCN`.