Correct statements regarding Arrhenius equation among the following are : A. Factor e^ -E a / R T corresponds to fraction of molecules having kinetic energy less than Ea. B. At a given temperature, lower the Ea, faster is the reaction. C. Increase in temperature by about 10^ C doubles the rate of reaction. D. Plot of k vs 1 ~T gives a straight line with slope =- E a R . Choose the correct answer from the options given below :
C. B and C Only
The Arrhenius equation is given by k = A e^ -E_a/RT . Statement A: The factor e^ -E_a/RT represents the fraction of molecules having kinetic energy equal to or greater than the activation energy E_a. Thus, statement A is incorrect. Statement B: From the equation, as E_a decreases, the value of k increases, leading to a faster reaction rate. Thus, statement B is correct. Statement C: For many reactions, the temperature coefficient is approximately 2, meaning the rate of reaction doubles for every 10^ C rise in temperature. Thus, statement C is correct. Statement D: Taking the natural logarithm of the Arrhenius equation, k = A - E_a RT . Converting to base 10, k = A - E_a 2.303RT . A plot of k vs 1 T gives a straight line with slope = - E_a 2.303R . The statement says slope = - E_a R , which is only true for a k vs 1 T plot. Thus, statement D is incorrect. Therefore, statements B and C are correct.
Related: Chemistry — Chemical Kinetics · All PYQ Banks