Question

The solution of the nickel sulphate, in which a nickel rod is dipped , has been diluted $10$times. The potential of nickel electrode:
A. Decreases by $60\,$ $mV$
B. Increases by $30$ $mV$
C. Decreases by $30$ $mV$
D. Dncreases by $60\,$ $mV$

Answer 1

Hint: Before attempting this question, one must have prior knowledge about the concept of electrochemistry. Please go through all the important formulas and concepts of this topic.

Complete step by step answer:
- Electrochemistry is the study of electricity and how it relates to chemical reactions. In electrochemistry, electricity can be generated by movements of electrons from one element to another in a reaction known as redox or oxidation-reduction reaction.
- The electrolytic cell converts electrical energy to chemical energy. Here the electrodes are dipped in an electrolytic solution containing cations and anions.
- This question is based on the electrolytic cell concept.
Using Nernst equation:
$E = {E_0} + \dfrac{{0.059}}{n}\log \dfrac{{{M^{n + }}}}{M}$
$n = $number of electrons in the reaction.
The reaction of the question is : $N{i^{2 + }} + 2{e^ - } \to Ni$
In this equation $n = $2;
${M^{n + }} = N{i^{2 + }}$ concentration
 $M = Ni$ concentration
Solution is been diluted $10$times.
Solve the equation-
$E = {E_0} + \dfrac{{0.059}}{n}\log \dfrac{{{M^{n + }}}}{M}$
$ \Rightarrow E = {E_0} + \dfrac{{0.059}}{2}\log \dfrac{{N{i^{2 + }}}}{{Ni}}$
$ \Rightarrow E = {E_0} + \dfrac{{0.059}}{2}\log \dfrac{1}{{10}}$
$ \Rightarrow E = {E_0} - 0.03V$;
$ \Rightarrow {E_0} = E + 0.03V$
 The potential of nickel electrode
So, from the equation, it increases by $30$$mV$.
So the correct answer is “B”:

Additional Information: There are two types of electrochemical cells: galvanic, also called Voltaic, and electrolytic. Galvanic cells derive their energy from spontaneous redox reactions, while electrolytic cells involve non-spontaneous reactions and thus require an external electron source like a DC battery or an AC power source.

Note: An electrochemical cell can be created by placing metallic electrodes into an electrolyte where a chemical reaction either uses or generates an electric current.