Question

Consider the following data: Cu + Mn = 1.54 V (Mn is the anode). The copper solution is Cu2+
Mn + Unk = 0.91 V (Mn is the anode)
Unk + Cu = 0.60 V (Unk is the anode)
Use the standard reduction potentials from your text book to determine the most likely identity of the unknown metal ?

Answer 1

The potential of a cell is given by

Where are the standard reduction potential of cathode and anode respectively.

Given that

(As Mn is anode) ........(1)

We know that the Cu eelctrode is which has a reduction potential of

Hence,

Given that

(Since Mn is anode)

Using the third relation

Hence, the unknown electrode has a reduction potential ranging from -0.29 to -0.26 V.

Hence, the unknown is most likely Nickel metal.