# How do you determine the oxidation states of the elements in the compound H_2SO_4?

The oxidation number of $H$ is $+ I$, of $O$, $- I I$, and for sulfur, $+ V I$. The sum of the oxidation numbers equals the charge on the molecule, which is $0$. Can you similarly assign the oxidation numbers for sulfurous acid, ${H}_{2} S {O}_{3}$?