Question

Can you store ${\text{CuS}}{{\text{O}}_{\text{4}}}$ solution in zinc pot?

Answer 1

Any element lower in the series will have the potential to oxidize itself and replace any element above it in an electrolytic solution. If the cation in the solution has a higher value of reduction potential than the metal present in the container, it will reduce itself and will be displaced from the compound by the other metal.

Complete step by step answer:
According to the electrochemical series, if an element is present lower in the series, it has a higher potential of oxidising itself into cations than the elements above it. So, when a solid metal with lower reduction potential is placed in an electrolytic solution containing the cation of a higher reduction potential element, the element with higher reduction potential will reduce itself from cation to metal. The element with lower reduction potential will oxidise itself and replace the other element in the solution.
In the question, ${\text{CuS}}{{\text{O}}_{\text{4}}}$ in a solution will be present as ${\text{C}}{{\text{u}}^{{\text{2 + }}}}$ and ${\text{SO}}_{\text{4}}^{{\text{2 - }}}$ ion. When placed in a zinc pot, the zinc which has a lower reduction potential than copper will oxidize itself to form ${\text{Z}}{{\text{n}}^{{\text{2 + }}}}$ and will replace ${\text{C}}{{\text{u}}^{{\text{2 + }}}}$ ion in the solution. So after some time, the inner wall of the pot will contain copper in its reduced form ${\text{Cu}}$ while the solution will contain ${\text{Z}}{{\text{n}}^{{\text{2 + }}}}$ and ${\text{SO}}_{\text{4}}^{{\text{2 - }}}$ ion to form ${\text{CuS}}{{\text{O}}_{\text{4}}}$ solution.

$\therefore$ We cannot store ${\text{CuS}}{{\text{O}}_{\text{4}}}$ solution in a zinc pot.

Note:
The lower the reduction potential of an element, the higher the oxidation potential and the higher the tendency to get oxidised. The difference in reduction potential is the reason why utensils of some of the lower reduction potential elements like aluminium, zinc are not preferred to store food. They oxidize themselves and thus, the food becomes toxic due to the presence of ${\text{A}}{{\text{l}}^{{\text{3 + }}}}$ and ${\text{Z}}{{\text{n}}^{{\text{2 + }}}}$ ions.