Question

H2 → HCl → NaCl → Na2SO4 → BaSO4

Answer 1

H2+Cl2=2HCl HCl+NaOH=NaCl+H2O 2NaCl+H2SO4=Na2SO4+2HCl Na2SO4+Ba(OH)2=BaSO4+2NaOH

Answer 2

H2+Cl2=2HCl
HCl+NaOH=NaCl+H2O
2NaCl+H2SO4=2HCl+Na2SO4
Na2SO4+Ba(OH)2=2NaOH+BaSO4