Which type of electrochemical cell produces electricity spontaneously?

• A. Electrolytic cell
• B. Fuel cell
• C. Battery
• D. Galvanic cell

Answer: (D)

Spontaneous electricity production comes from galvanic cells. In a galvanic cell, a redox reaction proceeds without external energy because the electrode potentials create a driving force. Electrons flow from the anode—where oxidation happens—to the cathode—where reduction occurs—through an external circuit, delivering electrical energy. The driving force is a positive cell potential, which makes the Gibbs energy change negative (ΔG = -nFEcell); that thermodynamic favorability is what lets the cell produce electricity on its own. In contrast, electrolytic cells require external power to drive non-spontaneous reactions, while fuel cells generate electricity as long as fuel and oxidant are supplied, but their operation rests on the same spontaneous redox chemistry under proper conditions.