1) Na → Na2O → NaOH → NaCl
4Na + O2 = 2Na2O
Na2O + H2O = 2NaOH
NaOH + HCl = NaCl + H2O
2) Ca → CaO → Ca(OH)2 → CaO
2Ca + O2 = 2CaO
CaO + H2O = Ca(OH)2
Ca(OH)2 = CaO + H2O (при t)
3) S → SO3 → H2SO4 → K2SO4
2S + O2 = 2SO3
SO3 + H2O = H2SO4
H2SO4 + 2KOH = K2SO4 + 2H2O