Which of the following pair of metals, when coupled, will give maximum EMF for a voltaic cell? — Electrochemistry Chemistry Question

💡 Solution & Explanation

The EMF of a voltaic cell is maximized when coupling the strongest reducing agent (most negative standard reduction potential) with the strongest oxidizing agent (most positive standard reduction potential) available. Calcium (Ca, highly reactive, E° ~ -2.87 V) paired with Copper (Cu, E° = +0.34 V) gives the largest potential difference among the listed options.