А) Cr2O3 + 2NaOH = 2NaCrO2 + H2O
Cr2O3 + 2KOH = 2KCrO2 + H2O
Cr2O3 + 6HBr = 2CrBr3 + 3H2O
Б) NH4Cl + AgNO3 = AgCl + NH4NO3
NH4Cl + KOH = KCl + NH3 + H2O
2NH4Cl + Ca(OH)2 = CaCl2 + 2NH3 + 2H2O
В) Zn(OH)2 + 2NaOH = Na2[Zn(OH)4]
Zn(OH)2 + 2KOH = K2[Zn(OH)4]
Zn(OH)2 + 2HBr = ZnBr2 + 2H2O
Г) 3Ca + N2 = Ca3N2
Ca + 2H2O = Ca(OH)2 + H2
2Ca + O2 = 2CaO
Ответ: 4245