Question

If concentration of two weak bases are same D.O.I$\left(\alpha \right)$ are very less than their relative strength can be compared by:

• A. $\frac{{\left[O{H}^{-}\right]}_1}{{\left[O{H}^{-}\right]}_2}$
• B. $\frac{K_{b1}}{K_{b2}}$
• C. $\frac{{\alpha }_1}{{\alpha }_2}$
• D. $\frac{\sqrt{K_{b1}}}{\sqrt{K_{b2}}}$

Answer 1

Answer: (A), (D)

$\frac{{\left[O{H}^{-}\right]}_1}{{\left[O{H}^{-}\right]}_2}$
$\frac{\sqrt{K_{b1}}}{\sqrt{K_{b2}}}$

As we know,

Relative strength $=\frac{\left[O{H}^{-}\right]furnishedbyIbase}{\left[O{H}^{-}\right]furnishedbyIIbase}=\frac{{\left[O{H}^{-}\right]}_1}{{\left[O{H}^{-}\right]}_2}$ = $\frac{C_1{\alpha }_1}{C_2{\alpha }_2}$

According to Ostwald's dilution law, $k={\alpha }^2\times C$

since $\alpha$ is very small

and , If conc. of both bases are same, then

Relative strength $=\sqrt{\left(K_1/K_2\right)}$