Question

Study this chemical reaction: Cr + Cl₂ ---> CrCl₂

Then, write balanced half-reactions describing the oxidation and reduction that happen in this reaction.

Answer 1

Consider a reaction Cr + Cl ₂ CrCl ₂

Oxidation number of Cr changes from 0 to +2. Oxidation number of Cr is increased by two units, hence it is oxidized.

Oxidation number of Cl changes from 0 to -1. Oxidation number of Cl is decreased by one unit, hence it is reduced.  

Now, we can write balance half reactions as shown below.

Oxidation : Cr Cr ²⁺ + 2 e ^-

Reduction : Cl ₂ + 2 e ^- 2 Cl ^-