Question

The overall reaction 2Co3+(aq) + 2Cl–(aq) → 2Co2+(aq) + Cl2(g) has the standard cell voltage E°cell = 0.46 V. Given E° = 1.36 V for the reaction Cl2(g) + 2e– → 2Cl–(aq), calculate the standard reduction potential for the following the half reaction at 25°C: Co3+ + e– → Co2+

Answer 1

Answer: The standard reduction potential for reduction half reaction is 1.82 V

Step-by-step explanation:

The given chemical reaction follows:

`2Co^(3+)(aq.)+2Cl^(aq.)\rightarrow 2Co^(2+)(aq.)+Cl_2(g)`

Oxidation half reaction:
`2Cl^-\rightarrow Cl_2+2e^-`

Reduction half reaction:
`Co^(3+)+e^-\rightarrow Co^(2+)`

Substance getting oxidized always act as anode and the one getting reduced always act as cathode.

To calculate the
`E^o_(cell)` of the reaction, we use the equation:

`E^o_(cell)=E^o_(cathode)-E^o_(anode)`

We are given:

`E^o_(Cl_2/2Cl^-)=1.36V\\\\E^o_(cell)=0.46V`

Putting values in above equation, we get:

`0.46=E^o_(Co^(3+)/Co^(2+))-1.36\\\\E^o_(Co^(3+)/Co^(2+))=(0.46+1.36)V=1.82V`

Hence, the standard reduction potential for reduction half reaction is 1.82 V