For each of the following reactions, state whether it is an oxidation or a reduction. Then, for each one, write the balanced half-reaction.

a. Fe³+ (aq) → Fe²+ (aq)
b. 2O²- (aq) → O₂ (g)
c. Al³+ (aq) → Al(s)
d. Fe²+ (aq) → Fe(s)
e. Mg (s) → Mg²+ (aq)

1 answer

Straight forward. Just remember the definitions. Oxidation is the loss of electrons. Reduction is the gain of electrons. Here is a memory aid. LEO the lion goes GER. LEO = loss electrons oxidation. GER = gain electrons reduction.
a. Fe³+ (aq) → Fe²+ (aq)
Fe^3+ + e ==> Fe^2+ that's a GER so reduction.
b. 2O²- (aq) → O₂ (g)
2O2^2- ==> 2O2 +2e that's a LEO so oxidation
I shall be happy to check the others if you post your answers.