The acid formed by hydration of sulfur dioxide is....?

1 Answer
Jan 30, 2016

Is sulfurous acid, formally H_2SO_3.

Explanation:

You can still see these elaborate glass bubblers gathering dust in old laboratories that were expressly for this purpose.

SO_2(g) + H_2O(l) rarr H_2SO_3(aq)

This sulfurous acid is saturated SO_2(aq), i.e. SO_2*H_2O. This is still an acidic oxide that may be reacted (and titrated) with hydroxide ion.