Redox Displacement Reaction

Steps:

• Write ionic equation: Cl₂ + 2Br⁻ → 2Cl⁻ + Br₂
• Determine oxidation states: Cl changes from 0 in Cl₂ to -1 in Cl⁻ (reduction); Br changes from -1 in Br⁻ to 0 in Br₂ (oxidation)
• Apply definition: Oxidation is loss of electrons, so Br⁻ → Br₂ + 2e⁻
• Confirm: Chlorine acts as oxidizing agent, oxidizing bromide ions

Why A is correct:

• Bromide ions lose electrons (Br⁻ → ½Br₂ + e⁻), matching oxidation definition

Why the others are wrong:

• B: Chlorine atoms gain electrons (reduction), and reaction involves Cl₂, not Cl⁻
• C: Bromine atoms form in Br₂ (oxidized product); bromide ions are oxidized
• D: Reaction is redox, with electron transfer between species

Final answer: A