Question

For a reaction, the value of rate constant at 300 K is 6.0 ×10⁵ s^-1. The value of Arrhenius factor A at infinitely high temperature is :

• A. 6 × 10⁵ × e^-Ea/300R
• B. e^-Ea/300R
• C. \(\frac{6\times10^{-5}}{300}\)
• D. 6 × 10⁵

Answer 1

The Correct Option is D

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 gas constant, and \(T\) is the temperature.

At Infinitely High Temperature

At infinitely high temperature, \(e^{-\frac{E_a}{RT}}\) approaches 1, because the exponential term becomes negligible. Therefore, the rate constant \(k\) approaches the pre-exponential factor \(A\).

Given

The rate constant \(k\) at 300 K is \(6.0 \times 10^5 \, \text{s}^{-1}\).

Conclusion

Therefore, at infinitely high temperature, the Arrhenius factor \(A\) is: \[ \boxed{6 \times 10^5} \]