Question

Determine E o for the following reaction, using the given standard reduction potentials: Co 3+(aq) + Fe(s) → Co 2+(aq) + Fe 2+(aq) E o for Fe 2+(aq) = -0.44 V E o for Co 3+(aq) = 1.81 V

Answer 1

Answer : The standard cell potential of the reaction is, 2.25 V

Explanation :

The given balanced cell reaction is,

`CO^(3+)(aq)+Fe(s)\rightarrow CO^(2+)(aq)+Fe^(2+)(aq)`

From the reaction we conclude that, iron (Fe) undergoes oxidation by loss of electrons and act as an anode. Cobalt (Co) undergoes reduction by gain of electrons and thus act as cathode.

The standard values of cell potentials are:

Standard reduction potential of iron
`E^0_([Fe^(2+)/Fe])=-0.44V`

Standard reduction potential of cobalt
`E^0_([Co^(3+)/Co^(2+)])=1.81V`

Now we have to calculate the standard cell potential for the following reaction.

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

`E^0=E^0_([Co^(3+)/Co^(2+)])-E^0_([Fe^(2+)/Fe])`

`E^0=(1.81V)-(-0.44V)=2.25V`

Therefore, the standard cell potential of the reaction is, 2.25 V