2NaOH + CuSO4 = Na2SO4 + Cu(OH)2
2OH- + Cu2+ = Cu(OH)2
Pb(NO3)2+H2S = PbS+ 2HNO3
Pb(2+) + S(2-) = PbS
CuO + 2HCl = CuCl2 +H2O
CuO + 2H+ = Cu2+ + H2O
Na2CO3 + 2HCl = 2NaCl + H2O + CO2
CO32- + 2H+ = H2O + CO2
Fe(OH)3 + 3HNO3= Fe(NO3)3 + 3H2O
OH- + H+ = H2O