Question

Variation of the rate constant k with temperature is described by which equation?

(a) Arrhenius equation

(b) Monod equation

(c) Kirchoff’s equation

(d) Newton’s second law of thermodynamics

This question was addressed to me by my school teacher while I was bunking the class.

The query is from Basic Reaction Theory in portion Homogenous Reactions of Bioprocess Engineering

Answer 1

Right choice is (a) Arrhenius equation

Explanation: Temperature has a significant kinetic effect on reactions. Variation of the rate constant k with temperature is described by the Arrhenius equation:

k = A e^-E/RT

Where, k is the rate constant, A is the Arrhenius constant or frequency factor, E is the activation energy for the reaction, R is the ideal gas constant, and T is absolute temperature. According to the Arrhenius equation, as T increases, k increases exponentially.

Taking the natural logarithm of both sides of equation:

Thus, a plot of ln k versus 1/T gives a straight line with slope -E/R . For many reactions the value of E is positive and large, indicating a rapid increase in reaction rate with temperature.