Which Reaction is more likely to occur: Cu+2 + Al0 → Cu0 + Al+3 Cu0 + Al+3 → Cu+2 + Al0 Why?

Question

Which Reaction is more likely to occur:

1. Cu⁺² + Al⁰ → Cu⁰ + Al⁺³
2. Cu⁰ + Al⁺³ → Cu⁺² + Al⁰

Why?

Answer 1

Standard reduction potentials are...

Cu²⁺ + 2e- ==> Cu Eº = +0.34 V

Al³⁺ +3e- ==> Al Eº = -1.66 V

So the preferred reaction will be Cu²⁺ + Al ==> Cu + Al³⁺ (unbalanced)

The why is because of the standard reduction potentials where Cu2+ will be reduced and Al will be oxidized.