Question

Use the standard half-cell potentials listed below to calculate the standard cell potential for the following reaction occurring in an electrochemical cell at 25�C. (The equation is balanced.)

3 Cl2(g) + 2 Fe(s) --> 6 Cl-(aq) + 2 Fe3+(aq)

Cl2(g) + 2 e- --> 2 Cl-(aq); E� = +1.36 V

Fe3+(aq) + 3 e- -->Fe(s); E� = -0.04 V

+1.32 V

-1.32 V

-1.40 V

+1.40 V

+4.16 V

Answer 1

Answer: + 1.40 V

Step-by-step explanation:

The balanced chemical equation is:

`3Cl_2(g)+2Fe(s)\rightarrow 6Cl^-(aq)+2Fe^(3+)(aq)`

Here Fe undergoes oxidation by loss of electrons, thus act as anode. Chlorine undergoes reduction by gain of electrons and thus act as cathode.

`E^0=E^0_(cathode)- E^0_(anode)`

Where both
`E^0` are standard reduction potentials.

`E^0_([Fe^(3+)/Fe])=-0.04V`

`E^0_([Cl_2/Cl^-])=+1.36V`

`E^0=E^0_([Cl_2/Cl^-])- E^0_([Fe^(3+)/Fe])`

`E^0=+1.36-(-0.04V)=+1.40V`

The standard cell potential for the reaction is +1.40 V