What is the potential for electrons to flow from a metal to another substance called?

• A. Electrical potential
• B. Magnetical potential
• C. Electrochemical potential (ECP)
• D. Thermal potential

Answer: (C)

The driving force for electrons moving from a metal into another substance is described by the electrochemical potential. This quantity combines the chemical potential (the energy associated with the electrons’ state in the material) with the electrical potential (the energy from the electric field). When two substances are in contact, electrons will flow until their electrochemical potentials align, reaching equilibrium. That full, combined potential explains why electrons move, not just the voltage alone.

Electrical potential by itself is just the voltage, which drives charge separation but doesn’t account for how easily electrons can enter or leave a material due to its chemical environment. The other terms aren’t standard concepts for this situation, so they don’t accurately describe the actual driving force.