EMF of the cell Zn | Zn²⁺(aq) || Cu²⁺(aq) | Cu is independent of which of the following?

Quantity of Cu²⁺ and Zn²⁺ in solution

The correct answer is option 1. Quantity of Cu²⁺ and Zn²⁺ in solution.

The EMF (Electromotive Force) of an electrochemical cell is a measure of the cell's ability to push electrons through an external circuit. In the context of the cell \(Zn | Zn^{2+} (aq) || Cu^{2+} (aq) | Cu\), the EMF is determined by the difference in standard electrode potentials (\(E^{\circ}\)) between the two half-reactions occurring at the electrodes.

For this cell, the half-reactions are:

At the anode (oxidation): \(Zn \rightarrow Zn^{2+} + 2e^-\) (standard electrode potential: \(E^{\circ}_{\text{anode}}\))

At the cathode (reduction): \(Cu^{2+} + 2e^- \rightarrow Cu\) (standard electrode potential: \(E^{\circ}_{\text{cathode}}\))

The overall cell potential (\(E_{\text{cell}}\)) is calculated by subtracting the standard electrode potential of the anode from that of the cathode:

\(E_{\text{cell}} = E^{\circ}_{\text{cathode}} - E^{\circ}_{\text{anode}}\)

The standard electrode potentials (\(E^{\circ}\)) are intrinsic properties of the electrode-electrolyte interfaces and are not affected by changes in the concentrations of the ions in solution. Therefore, the EMF of the cell is independent of the quantity of \(Cu^{2+}\) and \(Zn^{2+}\) ions present in solution.

In summary, the EMF of the cell \(Zn | Zn^{2+} (aq) || Cu^{2+} (aq) | Cu\) is determined solely by the standard electrode potentials of the half-reactions involved and is not influenced by changes in the concentrations of the ions in solution.