At `80^(@)C` distilled water has `[H_(3)O^(+)]` concentration equal `[OH^(-)] 1xx10^(-6) "mole"//litre`. The value of `K_(w)` at this temperature will be

Options

A. `1 xx 10^(-8)`
B. `1 xx 10^(-12)`
C. `1 xx 10^(-14)`
D. `1 xx 10^(-6)`

Answer

B

Explanation

`[H_(3)O^(+)]=[OH^(-)]=1xx10^(-6) mol L^(-1)`
Thus `K_(w)=[H_(3)O^(+)][OH^(-)]`
`=1 xx 10^(-6)xx1xx10^(-6)`
`K_(w)=1xx10^(-12)`