Question

The dissociation constant of a weak base (BOH) is 1.8 × 10⁻⁵. Its degree of dissociation in 0.001 M solution is ____________.

Options

• `sqrt(1.8 xx 10^-1)`

• `sqrt(1.8 xx 10^-2)`

• `sqrt(1.8 xx 10^-3)`

• `sqrt(1.8 xx 10^-4)`

Answer 1

The dissociation constant of a weak base (BOH) is 1.8 × 10⁻⁵. Its degree of dissociation in 0.001 M solution is `underline(sqrt(1.8 xx 10^-2))`.

Explanation:

K_b = 1.8 × 10⁻⁵, c = 0.001 M

K_b = α²c

∴ α = `sqrt("K"_"b"/"c") = sqrt((1.8 xx 10^-5)/0.001) = sqrt(1.8 xx 10^-2)`