Question

A standard hydrogen electrode has zero electrode potential because:

• A. the electrode potential is assumed to be zero
• B. hydrogen is less reactive
• C. hydrogen atom has only one electron
• D. hydrogen atom can gain or lose an electron

Answer 1

The correct option is A the electrode potential is assumed to be zero

The potential of an individual half-cell cannot be measured directly. Only the difference between the two half-cell potentials (emf) can be measured.
Hence,
Hydrogen is used as standard electrode and other electrode's potential is measured with respect to hydrogen so potential of hydrogen is arbitrarily assumed to be zero for standard measurements.