# What is the %-ionization in a 0.20M solution of a weak acid, HA?

Aug 12, 2017

Unknown.......

#### Explanation:

You have the weak acid undergoing protonolysis in aqueous solution:

$H A \left(a q\right) + {H}_{2} O \left(l\right) \rightarrow {H}_{3} {O}^{+} + {A}^{-}$

Now we calculate the extent of this equilibrium by use of the equation, ${K}_{a} = \frac{\left[{H}_{3} {O}^{+}\right] \left[{A}^{-}\right]}{\left[H A\right]}$. But we ain't got a value of ${K}_{a}$; typical values of ${K}_{a}$ for the weak acid ${H}_{3} C - C {O}_{2} H$, ${K}_{a} = 1.73 \times {10}^{-} 5$; for $H F$, ${K}_{a} = 6.76 \times {10}^{-} 4$; and for water, ${K}_{a} = {10}^{-} 14$.

Over to you......