Quiz Can copper sulphate solution be stored in a pot made of zine?...

Can copper sulphate solution be stored in a pot made of zine? Explain…

CBSE Chemistry class 12 question and answer | Can copper sulphate solution be stored in a pot made of zine?

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February 27, 2024

Can copper sulphate solution be stored in a pot made of zine?
Explain with the help of the value of E° cell.
(E° Cu2+ / Cu = 0.34 V)
(E° Zn2+ / Zn = – 0.76 V)

Ans.

No, copper sulfate solution cannot be stored in a pot made of zinc. This is due to the potential for a galvanic cell reaction to occur between zinc and copper ions in the copper sulfate solution, leading to corrosion of the zinc pot.

The standard electrode potential ( $E °$ ) values provided for the reactions involving copper ( $C u^{2+} / C u$ ) and zinc ( $Z n^{2+} / Z n$ ) ions are as follows:

$E °_{C u 2+ / C u} = 0.34 V$
$E °_{Z n 2+ / Z n} = - 0.76 V$

For a galvanic cell reaction, the overall cell potential ( $E °_{cell}$ ) is determined by the difference between the standard electrode potentials of the two half-cells:

$E °_{cell} = E °_{cathode} - E °_{anode}$

In this case, copper ions ( $C u^{2+}$ ) from the copper sulfate solution would act as the cathode, and zinc metal ( $Z n$ ) from the zinc pot would act as the anode.

Given the standard electrode potentials, the overall cell potential ( $E °_{cell}$ ) for the reaction would be:

$E °_{cell} = E °_{C u 2+ / C u} - E °_{Z n 2+ / Z n}$ $E °_{cell} = (0.34 V) - (- 0.76 V)$ $E °_{cell} = 1.10 V$

The positive value of $E °_{cell}$ indicates that the reaction is spontaneous, and thus, there would be a tendency for zinc metal to undergo oxidation (loss of electrons) and dissolve into the copper sulfate solution. This would result in corrosion of the zinc pot.

To prevent such corrosion, it’s important to avoid storing copper sulfate solution in a container made of zinc or any other metal with a higher negative standard electrode potential than zinc.