Question

If C is the concentration of a weak acid and $\alpha$ is its degree of ionisation,dissociation constant of the acid is given by:

• A. $\frac{C}{1-\alpha }$
• B. $\frac{C{\alpha }^2}{1-\alpha }$
• C. $\frac{C(1-\alpha )}{{\alpha }^2}$
• D. $\frac{C\alpha }{1-\alpha }$

Answer 1

The correct option is B $\frac{C{\alpha }^2}{1-\alpha }$

$HA\rightleftharpoons H^{+}+A^{-}$

$t=0$. $C$.

$t_{eg}$ $C(1-\alpha )$ $C\alpha$ $C\alpha$

$\therefore K_{\alpha }=\frac{C\alpha .C\alpha \alpha }{C(1-a)}$

$=\frac{C{\alpha }^2}{1-\alpha }$