Percentage of base ‘B’ that forms ${\mathrm{BH}}^{+}$ in a 0.1M aqueous solution of B will be( ${\mathrm{K}}_{\mathrm{b}}$ of base, B = $1.6\times {10}^{-8}$ )

For a weak base, $\mathrm{\alpha } = \sqrt{\frac{{\mathrm{k}}_{\mathrm{b}}}{\mathrm{C}}} = \sqrt{\frac{1.6\times {10}^{-8}}{0.1}} = 4\times {10}^{-4}$

 $$\begin{gathered} \% \mathrm{of} \mathrm{ionization} =4 \times {10}^{-4}\times 100; \\ =4 \times {10}^{-2} \end{gathered}$$