What is indicated by a positive cell potential?

A positive cell potential indicates a spontaneous reaction in electrochemistry. The cell potential, also known as the electromotive force (EMF), is a measure of the tendency of a chemical species to be reduced. When the cell potential is positive, it signifies that the reaction can proceed in the forward direction without the need for external energy input, meaning it occurs naturally and spontaneously.

In electrochemical terms, the cell potential can be derived from the Gibbs free energy change (ΔG) of a reaction. A spontaneous reaction is characterized by a negative ΔG, and there is a direct relationship: when the cell potential is positive, ΔG is negative, thus confirming that the reaction is energetically favorable.

The concept of equilibrium state applies when the cell potential is exactly zero, indicating that the forward and reverse reactions occur at the same rate, and no net change is observed. A nonsensical value in electrochemistry would not apply to the context of cell potentials since they are well-defined, measurable quantities used to predict reaction spontaneity.

Therefore, a positive cell potential categorically signifies that the chemical reaction under consideration can proceed spontaneously, affirming that the correct answer aligns with this understanding.