Question

16. Given standard electrode potentials :-
Fe3+ + 3e Fe: E = -0.036 volt
Fe2+ + 2e- Fe; E° = -0.440 volt
The standard electrode potential Eº for
Fe3+ e----->Fe2+
(1)-0.476 volt (2) -0.440 volt
(3) 0.440 volt (4) 0.772 volt
​

Answer 1

Answer:0.772 volt

Explanation: Since, standard reduction potential is an intensive property means E does not change if half reaction is multiplied by an integer. Hence, According to formula given below , we can solve the above problem.

Delta G = - nFE cell

Answer 2

Answer:

The standard electrode potential Eº is 0.772V

Explanation:

Given standard electrode potentials:

              $Fe^{3+} + 3e^{-} \rightarrow Fe: E = -0.036 V$

              $Fe^{2+} + 2e^{-} \rightarrow Fe: E = -0.440 V$

The free energy for reaction 1 is $\Delta G^{1} =-nFE=-3\times F\times -0.036$

The free energy for reaction 2 is $\Delta G^{2} =-nFE=-2\times F\times -0.440$

Then the free energy for $Fe^{3+} + e^{-} \rightarrow Fe^{2+}$ is

                   $\Delta G^{0} =\Delta G^{1}- \Delta G^{1}$

$\implies - 1\times F \times E^{0} =(-3\times F\times -0.036) -(-2\times F\times -0.440)$

$\implies -E^{0} =0.108 -0.88=-0.772$

$\implies E^{0} =0.772V$

Therefore, the standard electrode potential Eº is 0.772V