A solution saturated in lime water has a pH of 12 Then the `K_(sp)` for `Ca(OH)_(2)` is `:`

Options

A. `3.2xx10^(-3)`
B. `1.25xx10^(-7)`
C. `5.00xx10^(-7)`
D. `3.2xx10^(-4)`

Answer

2

Explanation

`pH=12" "implies" "-log(H^(+))=12implies`
`log[H^(+)]-12" "Ca(OH)_(2)hArr2OH^(-)+Ca^(2+)`
`[H^(+)]=10^(-12)`
`[OH^(-)]=(10^(-4))/(10^(-14))=10^(-2)`
`K_(sp)=[Ca^(2+)][OH^(-)]^(-2)" "[Ca^(2+)]=(1)/(2)[OH^(-)]`
`(10^(-2))xx((1)/(2)xx10^(-2))^(2)=1.25xx10^(-7)Ans.`