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^(-6)`
B. `1 xx 10^(-12)`
C. `1 xx 10^(-9)`
D. `1 xx 10^(-15)`

Answer

B

Explanation

`[H_(3)O^(+)]=1 xx 10^(-6)` mol `L^(-1)`
or `[H^(+)]=1 xx 10^(-6)` mol `L^(-1)`
As for distilled water `[H^(+)]=[OH^(-)]`
`[H^(+)]=[OH^(-)]= 1 xx 10(-6) ` mol `L^(-1)`
`K_(w)=[H^(=)][OH^(-)]`
`=10^(-12)mol^(2)L^(-2)`