Answer: The chemical formula for sulfurous acid is

Step-by-step explanation:
Sulfurous acid consists of 3 elements which are hydrogen, sulfur and oxygen atoms.
This compound is made by the combination of hydrogen ion
and sulfite ion

By criss-cross method, the oxidation state of the ions are exchanged and they form the subscripts of the opposite ions. This results in the formation of a neutral compound.
Thus, the chemical formula for this compound is
