The `pH` of `0.05M` aqueous solution of diethy`1` amine is `12.0` . Caluclate `K_(b)`.

Explanation

`pOH = 14 - pH = 14 - 12 = 2`
`[OH^(-)] = 10^(-2)`
`{:((C_(2)H_(5))_(2)NH+H_(2)O,hArr,(C_(2)H_(5))_(2)NH_(2)^(+),+,OH^(-)),((0.05 - 0.01),," "0.01,,0.01):}`
`K_(b) = ([(C_(2)H_(5))_(2)NH_(2)^(+)][OH^(-)])/([(C_(2)H_(5))_(2)NH]) = (0.01xx0.01)/(0.04) = 2.5 xx 10^(-3)`