For the cell Zn \| Zn2+ \|\| Cu2+ \| Cu, if the concentration of both, Zn2+ and Cu2+ ions are double — Electrochemistry Chemistry Question

💡 Solution & Explanation

According to the Nernst equation, the cell potential is given by $E = E^\circ - \frac{0.0591}{2} \log \frac{[Zn^{2+}]}{[Cu^{2+}]}$. If both concentrations are doubled, their ratio remains unchanged, and thus the logarithmic term and the EMF remain exactly the same.