PrepZii

formula

Ostwald Dilution Law

The Ionic Equilibrium section opens with weak acid and weak base dissociation.

Weak acid

K_a=\frac{[H^+][A^-]}{[HA]}=\frac{[C\alpha][C\alpha]}{C(1-\alpha)}=\frac{C\alpha^2}{1-\alpha}

\alpha\ll1\Rightarrow 1-\alpha\simeq1\quad\text{or}\quad K_a=C\alpha^2\quad\text{or}\quad \alpha=\sqrt{\frac{K_a}{C}}=\sqrt{K_a\times V}

Weak base

\alpha=\sqrt{\frac{K_b}{C}}

$\alpha$

degree of dissociation

$C$

concentration