Write a balanced overall reaction given the unbalanced 1/2 reactions

Question

Na—> Na+

Au3+—>Au

Overall reaction?

Answer 1

Na is going from zero oxidation to 1+, so it is being oxidized.

Au is going from 3+ oxidation to zero, so it is being reduced.

Na ===> Na⁺ + 1e- ... oxidation 1/2 reaction

Au³⁺ + 3e- ==> Au ... reduction 1/2 reaction

We must multiply the oxidation reaction by 3 to equalize the number of electrons, so we have...

3Na ==> 3Na⁺ + 3e- and combining this with the reduction reaction we have...

3Na + Au³⁺ ==> 3Na⁺ + Au ... OVERAL REACTION