Question

Na-->Na2O-->NaOH-->Na2SO4-->NaNO3​

Answer 1

1) 2Na + Na₂O₂ →t°,p→ 2Na₂O

2) Na₂O + H₂O → 2NaOH

3) 2NaOH + SO₃ → Na₂SO4 + H₂O

4) Na₂SO4 + Ba(NO₃)₂ → 2NaNO₃ + BaSO4↓