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For a reaction the activation energy Ea=...

For a reaction the activation energy `E_a=0` and the rate constant=`3.2 times 10^6 sec^-1` at 300K. What is the value of rate constant at 310K?

A

`6.4 times 10^6 sec^-1`

B

`6.4 times 10^12 sec^-1`

C

`3.2 times 10^6 sec^-1`

D

0

Text Solution

AI Generated Solution

The correct Answer is:
To find the value of the rate constant at 310 K given that the activation energy \(E_a = 0\) and the rate constant \(k_1 = 3.2 \times 10^6 \, \text{s}^{-1}\) at 300 K, we can use the Arrhenius equation. ### Step-by-Step Solution: 1. **Understanding the Arrhenius Equation**: The Arrhenius equation is given by: \[ k = A e^{-\frac{E_a}{RT}} \] where: - \(k\) is the rate constant, - \(A\) is the pre-exponential factor, - \(E_a\) is the activation energy, - \(R\) is the universal gas constant (approximately \(8.314 \, \text{J mol}^{-1} \text{K}^{-1}\)), - \(T\) is the temperature in Kelvin. 2. **Using the Logarithmic Form**: We can also express the change in rate constants with temperature using the logarithmic form: \[ \log \frac{k_2}{k_1} = \frac{E_a}{2.303R} \left( \frac{1}{T_1} - \frac{1}{T_2} \right) \] 3. **Substituting Known Values**: Given: - \(E_a = 0\) - \(k_1 = 3.2 \times 10^6 \, \text{s}^{-1}\) at \(T_1 = 300 \, \text{K}\) - \(T_2 = 310 \, \text{K}\) Substituting these values into the equation: \[ \log \frac{k_2}{3.2 \times 10^6} = \frac{0}{2.303R} \left( \frac{1}{300} - \frac{1}{310} \right) \] 4. **Simplifying the Equation**: Since \(E_a = 0\), the right-hand side becomes zero: \[ \log \frac{k_2}{3.2 \times 10^6} = 0 \] 5. **Exponentiating Both Sides**: This implies: \[ \frac{k_2}{3.2 \times 10^6} = 10^0 = 1 \] Therefore: \[ k_2 = 3.2 \times 10^6 \, \text{s}^{-1} \] 6. **Final Answer**: Thus, the value of the rate constant at 310 K is: \[ k_2 = 3.2 \times 10^6 \, \text{s}^{-1} \] ### Conclusion: The correct answer is \(3.2 \times 10^6 \, \text{s}^{-1}\), which corresponds to option three.
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