10. Na₂O → NaOH → Na₂SO₄ → NaNO₃

\(Na_2O+H_2O\rightarrow2NaOH\)

\(2NaOH+H_2SO_4\rightarrow Na_2SO_4+2H_2O\)

\(Na_2SO_4+Ba(NO_3)_2\rightarrow2NaNO_3+BaSO_4\downarrow\)

Ответ: Na₂O → NaOH → Na₂SO₄ → NaNO₃.