Question

Which half-reaction is most easily reduced? Al3+ + 3e- Al = -1.66 V Cu2+ + 2e- Cu = 0.34 V Fe3+ + e- Fe2+ = 0.77 V Na+ + e- Na = -2.71 V Pb2+ + 2e- Pb = -0.13 V

Answer 1

The answer is Fe3+ + e- Fe2+ =

Answer 2

Answer:

The half-reaction Fe³⁺  + e⁻ → Fe²⁺  E°= 0.77 V is most easily reduced.

Explanation:

Oxidation-reduction reactions or redox reactions are those in which an electron transfer occurs between the reagents. An electron transfer implies that there is a change in the number of oxidation between the reagents and the products.

The gain of electrons is called reduction and the loss of electrons oxidation. That is to say, there is oxidation whenever an atom or group of atoms loses electrons (or increases its positive charges) and in the reduction an atom or group of atoms gains electrons, increasing its negative charges or decreasing the positive ones.

So, electron donors are called reducers and electron acceptors are called oxidants.

 The reduction potential  is the tendency to reduce against a standard hydrogen electrode, taken as a reference with a potential equal to zero. The reduction potential is generally in standard conditions, that is, 1 M with respect to solute concentrations in solution and 1 atm for gases.

The more positive the standard reduction potential is, the greater the tendency towards reduction. On the contrary, the more negative the standard potential for reduction, the less tendency it has to reduce, that is, the greater the tendency for the reaction to take place in the opposite direction to what is written.

The most positive standard reduction potential is 0.77 V, belonging to the half-reaction:

Fe³⁺  + e⁻ → Fe²⁺  E°= 0.77 V

So, the half-reaction Fe³⁺  + e⁻ → Fe²⁺  E°= 0.77 V is most easily reduced.