Question

Consider the following data: Which of the five iron species (FeO_4^2-, Fe_2O_3, Fe^3+, Fe^2+, Fe) is the strongest oxidizer and which one should be the easiest to oxidize? The standard hydrogen electrode is connected with an inert electrode containing Fe^3+ ions in water as shown: Which of the electrodes is the cathode and which is the anode? Which way the electrons should move through the wire? Write the balanced chemical reaction taking place in the battery. Which of the five iron species should be oxidized under the standard conditions? Write a balanced reaction equation. Which of the five iron species can be reduced by water? Write a balanced reaction equation. Write a balanced half-reaction for E degree (FeO_4^2-/Fe_2O_3).

Answer 1

Strongest Oxidizer : The species which readily oxidizes other by reducing itself.

The species undergo easy oxidization will be the poor oxidizer.

In given 5 species, Fe has 0 oxidation state and this will readily undergo oxidation. So Fe is the easiest to oxidize.

And Fe has +6 oxidation state in FeO₄^2- it has tendency to accept electrons and so it is strongest oxidizer.

b).

Since Fe reduction potential is more negative than H , Fe acts as anode and H will be cathode.

Electrons flow will be from anode to cathode.

Balanced reaction

Oxidatation half              2Fe (s) -- >2 Fe³⁺ + 6 e-

Reduction half                 3H2 + 6 e- - > 6 H+

                                            ----------------------------------

Overall reaction         2 Fe(s) + 3 H2 -- > 2 Fe³⁺ + 6 H⁺

c) At standard condition

Fe²⁺

Fe -- > Fe²⁺ + 2 e-

Since it has lowest more negative reduction potential.

d).

Fe is the species which will be reduced by water

2Fe(s) +3 H2O (l) --- > Fe2O3(s) +3 H2 (g)

e).

Balanced half reaction :

Fe2O3 ---- > 2FeO4^2- + 6 e-