Question

pH of a saturated solution fo magnesium hydroxide in water at `298K` is 10. The solubility of the hydroxide in water at 298 K is
A. `5xx10^(-5)molL^(-1)`
B. `5xx10^(-12)molL^(-1)`
C. `1xx10^(-4)molL^(-1)`
D. `1xx10^(-10)molL^(-1)`

Answer 1

Correct Answer - A
`Mg(OH)_(2)iffMg^(2+)+2OH^(-)`
pH of `Mg(OH)_(2)` solution is 10
`becausepOH=4`
So `[OH^(-)]=10^(-4)`
`[OH^(-)]=2xx"solubility"`
`because "solubility"=(10^(-4))/(2)=0.5xx10^(-4)=5xx10^(-5)molL^(-1)`