The electrode potential becomes equal to the standard electrode potential when the reactants and products concentration ratio is

equal to 1

The correct answer is option 1. equal to 1.

Let us delve deeper into why the electrode potential becomes equal to the standard electrode potential (\( E^\circ \)) when the reactants and products concentration ratio is equal to 1.

The Nernst equation describes how the electrode potential (\( E \)) of an electrochemical cell varies with the concentration (or activity) of reactants and products. It is given by:

\(E = E^\circ - \frac{0.0591}{n} \log Q \)

where:

\( E^\circ \) is the standard electrode potential,

\( n \) is the number of moles of electrons transferred in the reaction,

\( Q \) is the reaction quotient, defined as \(\frac{[\text{products}]}{[\text{reactants}]}\).

Standard Conditions:

Under standard conditions (typically 1 M concentration for solutions):

\( Q = 1 \), because \(\frac{[\text{products}]}{[\text{reactants}]} = \frac{1}{1} = 1\). At standard conditions, the electrode potential (\( E \)) of the cell is equal to \( E^\circ \):

\( E = E^\circ - \frac{0.0591}{n} \log 1 = E^\circ\)

Explanation:

Equality Condition: When \( Q = 1 \), the logarithmic term in the Nernst equation becomes zero (\(\log 1 = 0\)). This results in \( E = E^\circ \).

Significance: This condition signifies that the cell is operating under standard conditions where the activities (or concentrations, in dilute solutions) of the reactants and products are exactly at their standard states.

Implications: When \( E = E^\circ \), the measured electrode potential corresponds directly to the standard electrode potential (\( E^\circ \)). This is important for electrochemical measurements because it provides a reference point and allows determination of equilibrium constants and standard Gibbs free energy changes (\( \Delta G^\circ \)).

Conclusion:

Therefore, the electrode potential becomes equal to the standard electrode potential (\( E^\circ \)) when the reactants and products concentration ratio is equal to 1. This condition ensures that the cell is under standard conditions, where the measured potential accurately reflects the inherent tendency of the redox reaction at equilibrium.