1) Na2S+Ba(OH)2 =ВаS + 2NaOH
+ 2- 2+ - 2+ 2- + -
2Na + S + Ba + 2OH = Ba + S + 2Na + 2OH
2) NaCl+AgNO3= NaNO3 + AgCl
+ - + - + -
Na + Cl + Ag + NO3 = Na + NO3 + AgCl
+ -
Ag + Cl = AgCl (осадок)
3) NaOH+H2SO4 =Na2SO4 + H2O
+ - + 2- + 2-
Na + OH +2H + SO4 = 2Na + SO4 + H2O
- +
OH + 2H =H2O