Question

The cell potential becomes equal to E⁰ when

• A. Equilibrium constant is 1
• B. Equilibrium constant is 10
• C. Equilibrium constant is 100
• D. None of these

Answer 1

Answer: (A)

Equilibrium constant is 1

Answer 2

The cell potential $E_{cell}$ becomes equal to the standard cell potential $E^0_{cell}$ when the reaction quotient Q is 1, as per the Nernst equation. If the equilibrium constant K is 1, then the standard cell potential $E^0_{cell}$ is 0. In this specific case, the condition $E_{cell} = E^0_{cell}$ implies $E_{cell} = 0$, which means the system is at equilibrium. At equilibrium, Q = K, so if K=1, then Q=1. Thus, when K=1, it implies a scenario where $E_{cell} = E^0_{cell}$ (both are zero) and Q=1.