Na2SO4 => NaOH => Na2O => NaOH => NaCl

Question

Na2SO4 => NaOH => Na2O => NaOH => NaCl

Answer 1

1) Na2SO4 + KOH = NaOH + K2SO4

2) 2NaOH = (t) Na2O + H2O

3) Na2O + H2O = 2NaOH

4) NaOH + KCl = NaCl + KOH