Question

The reduction potential of an electrode can be increased by:
(A) Increasing the area of the electrode
(B) Decreasing the temperature
(C) Increasing the temperature
(D) Increasing the concentration of metal ions

Answer 1

Hint : Reduction potential is an inherent property of a particular chemical entity to accept electrons and get itself reduced. Unit of measurement of reduction potential is either in millivolts or Volts. As the value of reduction potential increases the tendency of chemical species to get reduced also increases.

Complete Step By Step Answer:
Reduction potential of any chemical species can depend on a number of factors like temperature of operating conditions, surface area of the cell, concentrations of ions present in cell and many other factors also.
Reduction potential of any chemical cell remains independent of changes in area of electrode because reduction potential changes only when the process of reduction takes place in the cell and on changing the area of electrode there is no change in rate of process of reduction.
When we decrease the temperature of a chemical cell the process of dissociation of electrolytes present in the cell decreases as a result of which available number of ions for reduction also decreases which results in decrease in reduction potential of the cell.
When we increase the temperature of a chemical cell the process of dissociation of electrolytes present in the cell increases as a result of which the available number of ions for reduction also increases which results in an increase in reduction potential of the cell. As the temperature increases the number of ions increases in the cell and reduction potential increases.
On increasing the concentration of metal ions in the chemical cell it will result in collision of ions among them and decreases the mobility of ions to reach the electrode to get reduced. Due to decrease in the number of ions at electrodes which are meant to be reduced, it will result in decrease of reduction potential of chemical cells.
Hence, from the above discussion we see that on increasing the temperature the reduction potential of an electrode can increase.
Therefore the option $\left( C \right)$ is correct.

Note :
Electrode potential of a cell is of two types: oxidation potential and reduction potential.
The electrode potential of any cell is always taken as a reduction potential for both the electrodes of the cell.