How do I write balance equations for this redox reaction NaBr + Cl2 ===> NaCl + Br2 by the half reaction method?

Question

How do I write balance equations for this redox reaction NaBr + Cl2 ===> NaCl + Br2 by the half reaction method?

Answer 1

Break it up into a reduction half reaction and an oxidation half reaction

NaBr + Cl₂ ==> NaCl + Br₂

Since Cl₂ goes from zero oxidation state to 1- oxidation state, it has been reduced

Cl₂ ==> Cl- ... reduction half reaction (we don't need the Na as it is a spectator)

Cl₂ ==> 2Cl- ... balanced for Cl

Cl₂ + 2e- ==> 2Cl- ... balanced for charge and this is the final reduction half reaction

Since Br goes from -1 oxidation state to zero oxidation state, it has been oxidized

Br^- ==> Br₂ ... oxidation half reaction (we don't need the Na as it is a spectator)

2Br^- ==> Br₂ ... balanced for Br

2Br^- ==> Br₂ + 2e- ... balance for charge and this is the final oxidation half reaction

Both half reaction have 2 e- transferred so we can simply add the two half reactions and cancel the electrons.

Cl₂ + 2Br^- ==> 2Cl^- + Br₂ ... balanced redox reaction

If you want to put back the spectator Na, we have...

Cl₂ + 2NaBr ==> 2NaCl + Br₂ ... balanced redox reaction