Answer:
Na₂SO₃
Explanation:
We can use the criss-cross method to work out the formula.
1. Write the symbols of the anion and cation.
Na¹⁺ SO₃²⁻
2. Criss-cross the numbers of the charges to become the subscripts of the other ion (see image).
3. Write the formula with the new subscripts.
Na₂(SO₃)₁
4. Omit all subscripts that are 1.
The formula becomes Na₂SO₃.
