Question

Given these standard reduction potential, what is the standard reduction potential for:

`Co^(3+)(aq) + 3e^(-) rightarrow Co(s)`?
`Co^(3+)(aq) + e^(-) rightarrow Co^(2+)(aq) E^(@) = 1.82V`
`Co^(2+)(aq) + 2e^(-) rightarrow Co(s) E^(@) = -0.28V`

A. 2.10V

B. 1.54v

C. 1.26v

D. 0.42V

Answer 1

Correct option is (D) 0.42 V

Standard reduction potentials is the reduction potential of molecules under standard conditions and are used for the measurement of molecules' tendency to reduce. Reduction means the addition of electrons.

Standard reduction potential is related to the standard hydrogen electrode (SHE) which is taken as a reference electrode. The arbitrary value of the potential of SHE is taken as 0.00V. The reduction potential measures the reducing tendencies for a species. By comparing the two reduction potentials for two reactions, we will be able to determine how a reaction will proceed.

According to the question, we have given two standard reduction potentials.

CO³⁺(aq) + e^- → CO²⁺(aq)

When CO³⁺ is reduced CO²⁺. Here, the number of electron(n₁) transferred is equal to 1 and standard reduction value is \(E_1^o=1.82 V\)

CO²⁺(aq) + 2e^- → CO(s)

When CO²⁺ is reduced to CO. Here, the number of electrons(n₂) transferred is equal to 2 and the standard reduction value is \(E_2^o\) = -0.28 V

We have to calculate