Answer:
4 Ag⁺ + 2 H₂O + BrO⁻ → 4 Ag + BrO₃⁻ + 4 H⁺
Explanation:
In order to balance a redox reaction, we will use the ion-electron method.
Step 1: Identify both half-reactions
Reduction: Ag⁺ → Ag
Oxidation: BrO⁻ → BrO₃⁻
Step 2: Perform the mass balance adding H⁺ and H₂O where necessary
Ag⁺ → Ag
2 H₂O + BrO⁻ → BrO₃⁻ + 4 H⁺
Step 3: Perform the electrical balance adding electrons where necessary
1 e⁻ + Ag⁺ → Ag
2 H₂O + BrO⁻ → BrO₃⁻ + 4 H⁺ + 4 e⁻
Step 4: Multiply both half-reactions by numbers that secure that the number of electrons gained and lost are equal
4 × (1 e⁻ + Ag⁺ → Ag)
1 × (2 H₂O + BrO⁻ → BrO₃⁻ + 4 H⁺ + 4 e⁻)
Step 5: Add both half-reactions
4 e⁻ + 4 Ag⁺ + 2 H₂O + BrO⁻ → 4 Ag + BrO₃⁻ + 4 H⁺ + 4 e⁻
4 Ag⁺ + 2 H₂O + BrO⁻ → 4 Ag + BrO₃⁻ + 4 H⁺