At `25^(@)C`, the dissociation constant of a base, BOH id `1.0xx10^(-12)`. The concentration of hydroxyl ions in 0.01 M aqueous solution of the base would be

Options

A. `2.0 xx 10^(-6) mol L^(-1)`
B. `1.0 xx 10^(-5) mol L^(-1)`
C. `1.0 xx 10^(-6) mol L^(-1)`
D. `1.0 xx 10^(-7) mol L^(-1)`

Answer

2

Explanation

`{:(,BOH,hArr,B^(+),+,OH^(-)),("initial",C,,0,,0),("At.eq.",C-Calpha,,Calpha,,Calpha):}`
`K_(b) = (C^(2)alpha^(2))/(C(1-alpha)) = Calpha^(2) " assuming a " lt lt 1, 1 - a gt gt 1`
` 10^(-12) = 10^(-2) xx a^(2) , a^(2) = 10^(-10) , a = 10^(-5)`