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

Options

A. `1xx10^(-6)`
B. `1xx10^(-9)`
C. `1xx10^(-12)`
D. `1xx10^(-15)`

Answer

C

Explanation

`K_(w)=[H_(3)O^(+)][OH^(-)]`
Concentration of `H_(3)O^(+)` in distilled water `=1xx10^(-6) mol//L`.
Now `[H_(3)O^(+)]=[OH^(-)]`
`K_(w)=[1xx10^(-6)]xx[1xx10^(-6)]=1xx10^(-12)`