1) 2HBr + Zn = ZnBr₂+ H₂
2H⁺ + 2Br⁻ + Zn° = Zn²⁺ + 2Br⁻ + H₂°
2H⁺ + Zn° = Zn²⁺ + H₂°
2) 2HBr + MgO = MgBr₂ + H₂O
2H⁺ + 2Br⁻ + MgO = Mg²⁺ + 2Br⁻ + H₂O
2H⁺ + MgO = Mg²⁺ + H₂O
3) HBr + NaOH = NaBr + H₂O
H⁺ + Br⁻ + Na⁺ + OH⁻ = Na⁺ + Br⁻ + H₂O
H⁺ + OH⁻ = H₂O
4) HBr + AgNO₃ = AgBr↓ + HNO₃
H⁺ + Br⁻ + Ag⁺ + NO₃⁻ = AgBr↓ + H⁺ + NO₃⁻
Br⁻ + Ag⁺ = AgBr↓