# What does Ka stand for?

Jul 22, 2016

${K}_{a}$ is the acid dissociation constant, which are extensively tabulated for weak acids.

#### Explanation:

For an acid, $H A$, in water, we can represent its dissociation in this way:

$H A + {H}_{2} O r i g h t \le f t h a r p \infty n s {H}_{3} {O}^{+} + {A}^{-}$

Typically, we can quantify this equilibrium under standard conditions.

${K}_{a} = \frac{\left[{H}_{3} {O}^{+}\right] \left[{A}^{-}\right]}{\left[H A\right]}$

And thus for strong acids, for which the equilibrium lies to the right, we can deduce that ${K}_{a}$ is large.