Помогите!!!! s-so3-h2so4-caso4-cacl2-ca(oh)2

Question

Помогите!!!!
s-so3-h2so4-caso4-cacl2-ca(oh)2

Answer 1

2S+3O2=2SO3
H2O + SO3 = H2SO4 
Ca(OH)2 + H2SO4 = CaSO4 + 2H2O
CaSO4 + BaCl2 = CaCl2 + BaSO4
CaCl2 + 2NaOH = Ca(OH)2 + 2NaCl