Activation energy of a chemical reaction can be determined by

Options

A. determining the rate constant at standard temperature
B. determining the rate constants at two temperatures
C. determining probaiility of collision
D. using catalyst

Explanation

To determine the activation energy (Ea) of a chemical reaction, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Activation Energy**:
- Activation energy (Ea) is the minimum energy required for a chemical reaction to occur. It is a crucial factor in determining the rate of a reaction.

2. **Use the Arrhenius Equation**:
- The Arrhenius equation relates the rate constant (k) of a reaction to the temperature (T) and activation energy (Ea). The equation is given as:
\[ k = A e^{-\frac{E_a}{RT}} \]
- Where:
- \( k \) = rate constant
- \( A \) = pre-exponential factor (frequency factor)
- \( E_a \) = activation energy
- \( R \) = universal gas constant
- \( T \) = temperature in Kelvin

3. **Logarithmic Form of the Arrhenius Equation**:
- The Arrhenius equation can also be expressed in a logarithmic form:
\[ \log k = \log A - \frac{E_a}{2.303RT} \]
- This form is useful for plotting and determining activation energy.

4. **Determine Rate Constants at Two Different Temperatures**:
- To find the activation energy, we need to determine the rate constants (k1 and k2) at two different temperatures (T1 and T2). This can be expressed as:
\[ \frac{2.303 \log \frac{k_2}{k_1}}{T_2 - T_1} = \frac{E_a}{R \cdot T_1 \cdot T_2} \]

5. **Calculate Activation Energy**:
- Rearranging the equation allows us to solve for the activation energy (Ea):
\[ E_a = \frac{2.303 R (T_2 - T_1) \log \frac{k_2}{k_1}}{T_1 T_2} \]
- By substituting the values of k1, k2, T1, and T2 into this equation, we can calculate the activation energy.

### Conclusion:
- The activation energy of a chemical reaction can be determined by measuring the rate constants at two different temperatures and using the Arrhenius equation.