# Question #7231b

Feb 27, 2017

I assume you are referring to protons that are ionisable in acid-base processes. If so, the answer is two. One ionizes strongly, the other more weakly.

#### Explanation:

A molecule of sulfuric acid, ${H}_{2} S {O}_{4}$ has two protons that can ionize (transfer to a base).

The first ionization is strong, meaning that it occurs to an extent of 100% in water:

${H}_{2} S {O}_{4} + {H}_{2} O \rightarrow {H}_{3} {O}^{+} + H S {O}_{4}^{-}$

The second ionization is weaker (${K}_{a} = 1.2 \times {10}^{- 2}$):

$H S {O}_{4}^{-}$$+ {H}_{2} O \rightarrow {H}_{3} {O}^{+} + S {O}_{4}^{2 -}$