Use the equation to answer the question.
4NaCl + 2SO2 + _____H2O + _____O2 → _____Na2SO4 + 4HCl
Which numbers balance this equation?
1. 1, 2, 2
2. 1, 2, 4
3. 2, 1, 2
4. 2, 1, 4
The balanced equation is 4NaCl + 2SO2 + O2 + 2H2O → 2Na2SO4 + 4HCl.
Therefore, the correct numbers to balance this equation are 2, 1, 4.
So, the answer is 4. 2, 1, 4.