Question

Assertion: Copper sulphate solution can be stored in a zinc vessel.
Reason: \[{{E}^{{}^\circ }}_{C{{u}^{2+}}/Cu}=0.34V,{{E}^{{}^\circ }}_{Z{{n}^{2+}}/Zn}=-0.76V,{{E}^{{}^\circ }}_{A{{g}^{+}}/Ag}=0.80V\]
(A) Both assertion and reason are true and reason is the correct explanation of assertion.
(B) Both assertion and reason are true but reason is not a correct explanation of assertion.
(C) Assertion is true but Reason is false
(D) Assertion is false but reason is true.
(E) Both Assertion and Reason are false.

Answer 1

Hint: The substances which have lower reduction potentials are stronger reducing agents while those which have higher reduction potentials are stronger reducing agents. ${{E}^{\circ }}$ is known standard potential and it stands for reduction potential of the half cell.

Complete step by step answer:
It is known to you that the value of standard potentials helps in finding out whether a given redox reaction is feasible or not in the given direction from The E values of the two electrodes.
- Reduction potential or standard potential of the half cell describes the ability of the given half cell to get reduced.

- The standard reduction potential of copper, \[{{E}^{{}^\circ }}_{C{{u}^{2+}}/Cu}=0.34V\] and the standard reduction potential of zinc is \[{{E}^{{}^\circ }}_{Z{{n}^{2+}}/Zn}=-0.76V\] .
Since, the reduction potential of copper is more than that of zinc, this means that copper has a greater tendency to get reduced in comparison to zinc. Thus the reaction \[C{{u}^{2+}}+2{{e}^{-}}\to Cu\] occurs more readily than the reaction \[Z{{n}^{2+}}+2{{e}^{-}}\to Zn\] .

- So, the copper will get reduced and zinc will get oxidized. So, copper sulphate solution cannot be stored in a zinc vessel. The overall reaction can be given as below.
     \[Zn+CuS{{O}_{4}}\to ZnS{{O}_{4}}+Cu\]

- But the standard reduction potential of silver is more than that of copper, this means that silver has a greater tendency to get reduced in comparison to copper. The reduction potential of silver is 0.80V. That means that the reason is a true sentence.
So, the correct answer is “Option D”.

Note: It should be remembered to you that the electrochemical series can also be used to predict whether a metal can liberate hydrogen from the acid or not. Also, you should remember that with the help of electrochemical series, we can predict the relative oxidising or reducing strength of substances.