Question

Given: $E_{A{g}^{\oplus }/Ag}^{-}=0.80V$ , $E_{M{g}^{2+}/Mg}^{-}=-2.37V$;$E_{C{u}^{2+}/Cu}^{-}=0.34V$,$E_{H{g}^{2+}/Hg}^{-}=0.79V$
Which of the following statements is/are incorrect?
a.) $AgN{O}_3$ can be stored in copper vessels.
b.) $Cu{(N{O}_3)}_2$ can be stored in a magnesium vessel.
c.) $CuC{l}_2$ can be stored in a silver vessel.
d.) $HgC{l}_2$ can be stored in copper vessels.

Answer 1

Hint: Lower the reduction potential of any element higher is its reactivity.
The correct option is A, B and D
$E_{A{g}^{\oplus }/Ag}^{-}=0.80V$ , $E_{M{g}^{2+}/Mg}^{-}=-2.37V$;$E_{C{u}^{2+}/Cu}^{-}=0.34V$,$E_{H{g}^{2+}/Hg}^{-}=0.79V$

Complete answer:
The tendency of any element to stay in its oxidized form depends on its potential. Potential and its tendency to remain in its oxidized form are inversely proportional. Less the potential of any element more is its tendency to remain in its oxidized form.
Therefore, the sequence of the molecule to be in its oxidized form are:
$$M{g}^{2+}>C{u}^{2+}>H{g}^{2+}>A{g}^{+}$$
$$M{g}^{2+}$$will try to remain in its oxidized form whereas $$C{u}^{2+}$$ will be the most reduced form.

As per option A, $AgN{O}_3$is kept in a copper vessel. This statement is false as lower the reduction potential more is its reactivity so copper will react with $AgN{O}_3$and will replace silver by itself.
As per option B, $Cu{(N{O}_3)}_2$ can be stored in a magnesium vessel.
This statement is false because magnesium has lowest reductive potential therefore its reactivity is higher therefore it will react with $Cu{(N{O}_3)}_2$present in the container.
As per option C, $CuC{l}_2$ is kept in a silver vessel. Yes, it is true because the reduction potential of copper is higher than silver therefore, it can be stored in silver vessels.
As per option D, $HgC{l}_2$ is kept in a copper vessel. No, it can’t be stored in a copper container because lower the reduction potential higher is its reactivity. Reduction potential of copper is less than mercury so it can’t be stored in a copper container.
Therefore option A, B, D are incorrect.

Note:
 Lower the reduction potential of any element higher is its reactivity. Therefore, any compound cannot be stored in a vessel which has lower reduction potential to itself.