Final answer:
Sulfurous acid is a diprotic acid with Ka1 = 1.2 × 10-² and Ka2 = 6.2 × 10-⁹.
Step-by-step explanation:
Sulfurous acid is a diprotic acid, meaning it can ionize in two steps. The first stage of ionization occurs to a greater extent, with an acid ionization constant (Ka1) of 1.2 × 10-². The second stage of ionization occurs to a much lesser extent, with an acid ionization constant (Ka2) of 6.2 × 10-⁹.