# The acid and base dissociation constants

The acid dissociation constant (K_{a}) and base dissociation constant (K_{b}) values represent how easily an acid or base dissociates into ions, in a solution.

Strong acids and strong bases fully dissociate. They possess a _{a} > 1

Weak acids have a _{a} < 1

**Formulae**

**Figure 1.** Acid and base dissociation constant equations.

For acid and its conjugate base, or a base and its conjugate acid:

_{w} = K_{a} x K_{b}

Where _{w}

**Polyprotic acids and bases**

These species can donate or receive more than one proton, e.g. sulfuric acid. The second dissociation constant is usually extremely low.

**pK _{a} and pK_{b}**

_{a} and K_{b}

_{a} is the inverse log of K_{a}. The formula is -log[K_{a}]

_{b} is the inverse log of K_{b}. The formula is -log[K_{b}]