The electrode potential becomes equal to standard electrode potential when reactants and products concentaration ratio is .

Options

A. equal to `1`
B. greater than `1`
C. less than `1`
D. none of the above

Explanation

To solve the problem, we need to determine the concentration ratio of reactants and products when the electrode potential (E_cell) becomes equal to the standard electrode potential (E°_cell). We will use the Nernst equation to derive this relationship.

### Step-by-Step Solution:

1. **Understanding the Nernst Equation**:
The Nernst equation relates the cell potential (E_cell) to the standard cell potential (E°_cell) and the reaction quotient (Q_c):
\[ E_{cell} = E^{\circ}_{cell} - \frac{RT}{nF} \ln Q_c \]
where:
- \( R \) is the universal gas constant,
- \( T \) is the temperature in Kelvin,
- \( n \) is the number of moles of electrons transferred,
- \( F \) is Faraday's constant,
- \( Q_c \) is the reaction quotient, defined as the concentration of products divided by the concentration of reactants.

2. **Setting E_cell equal to E°_cell**:
According to the problem, we have:
\[ E_{cell} = E^{\circ}_{cell} \]
Substituting this into the Nernst equation gives:
\[ E^{\circ}_{cell} = E^{\circ}_{cell} - \frac{RT}{nF} \ln Q_c \]

3. **Simplifying the Equation**:
By rearranging the equation, we can cancel \( E^{\circ}_{cell} \) from both sides:
\[ 0 = -\frac{RT}{nF} \ln Q_c \]

4. **Solving for Q_c**:
Since the left side is zero, we can multiply both sides by -1:
\[ 0 = \frac{RT}{nF} \ln Q_c \]
This implies that:
\[ \ln Q_c = 0 \]

5. **Finding the Value of Q_c**:
The natural logarithm of a number is zero when that number is equal to 1:
\[ Q_c = e^0 = 1 \]

6. **Interpreting Q_c**:
The reaction quotient \( Q_c \) is defined as:
\[ Q_c = \frac{[\text{Products}]}{[\text{Reactants}]} \]
Therefore, if \( Q_c = 1 \), it means:
\[ \frac{[\text{Products}]}{[\text{Reactants}]} = 1 \]

### Final Answer:
The concentration ratio of products to reactants when the electrode potential becomes equal to the standard electrode potential is:
\[ \frac{[\text{Products}]}{[\text{Reactants}]} = 1 \]