Question

The same current was passed successively through a solution of zinc-ammonium sulphate and nickel-ammonium sulphate rendered alkaline with ammonia. The weights of zinc and nickel deposited in a certain time were found to be 22.89 g and 20.55 g, respectively. Given that the chemical equivalent weight of zinc is 32.7, what is the chemical equivalent weight of nickel?
(A) 58.71
(B) 29.36
(C) 14.39
(D) 36.42

Answer 1

Hint :Michael Faraday did substantial research on electrolysis of electrolyte solutions and melts. He was the first scientist to define the Laws of Electrolysis in quantitative terms. He developed two laws to describe the quantitative characteristics of electrolysis, which are today known as Faraday's laws of electrolysis, namely the first and second laws of electrolysis.

Complete Step By Step Answer:
Faraday's Law of Electrolysis is the first law of electrolysis.
It's one of the fundamental principles of electrolysis. It asserts that the amount of chemical reaction that takes place at any electrode under the influence of electrical energy is proportionate to the amount of electricity that passes through the electrolyte during electrolysis.
\[ \Rightarrow \dfrac{m}{Q} = Z\]
Faraday's Law of Electrolysis is the second law of electrolysis.
When the same amount of power is passed through the electrolytic solution during electrolysis, a number of distinct compounds are freed in proportion to their chemical equivalent weights (Equivalent weight is defined as the ratio of the atomic mass of metal and the number of electrons required for reducing the cation).
\[m \propto E\]
\[E = \dfrac{{{\text{Molar mass}}}}{{{\text{Valence}}}}\]
So here in our question,
0.531 g of zinc was deposited.
The amount of nickel that was deposited was 0.477 g.
Zinc's equivalence weight is 32.
Nickel's equivalent weight is?
That is something we are aware of.
$\dfrac{{{\text{ Amount of zinc deposited }}}}{{{\text{ Amount of nickel deposited }}}} = \dfrac{{{\text{ Eq}}{\text{. wt}}{\text{. of zinc }}}}{{{\text{ Eq}}{\text{. wt}}{\text{. of nickel }}}}$
Substituting the values we get,
$\dfrac{{0.531}}{{0.477}} = \dfrac{{32.7}}{{{\text{ Eq}}{\text{. wt}}{\text{. of nickel }}}}$
${\text{Eq}}{\text{.wt}}{\text{.of nickel}} = \dfrac{{32.7 \times 0.477}}{{0.531}} = 29.37$
$ \Rightarrow {\text{Eq}}{\text{.wt}}{\text{.of nickel}} = 29.37$
Hence option B is correct.

Note :
The nature of the substance being electrolyzed and the type of electrodes employed determine the outcome of an electrolytic reaction. An inert electrode, such as platinum or gold, does not participate in the chemical process and just serves as a source or sink for electrons. A reactive electrode, on the other hand, is a participant in the reaction.