Electra has mastered the basics of Nernst equation. She is now studying equilibrium constants relation with Nernst equation.
Electra was performing experiments with Nernst with a Daniel Cell. She noticed that when the reaction reaches equilibrium, the cell potential goes to 0.
She asked Nernst why this happened. His reply was
The first thing we need to understand here is that the reaction that is taking place here i.e the oxidation of Zn
Zn → Zn2+ + 2e-
Or the reduction of Cu
Cu2+ + 2e- → Cu
These reactions don’t really stop at equilibrium, because it is a dynamic equilibrium.
But the change in concentration of Cu2+ and Zn2+ don't change in the net reaction. This is the reason for no electrode potential because there is no net electron transfer.
Option a and b don’t make any sense in this context.
Option d is false because ions won’t be depleted completely.