chapter 6. CHEMICAL KINETICS class 12 chemistry textbook solution

3. Answer the following in brief.

xv. Explain graphically the effect of temperature on the rate of reaction.

Answer:- 

Comparison of fraction of molecules

i. The average kinetic energy of molecules is proportional to temperature.

ii. At a given temperature, a fraction of molecules with kinetic energy equal to or greater than E_a may lead to the product.

iii. Increasing the temperature results in an increased fraction of molecules with energy (E_a). Consequently, the reaction rate also increases.

iv. This concept is illustrated by plotting the fraction of molecules with a specified kinetic energy against kinetic energy for two different temperatures, T_1 and T_2 (where T_2 > T_1). The area between the curve and the horizontal axis is proportional to the total number of molecules, and this total area remains the same at both T_1 and T_2.

Comparison of the fraction of activated molecules at T_1 and T_2:

v. The shaded area, which represents the fraction of molecules with kinetic energy exceeding E_a, is larger at T_2 than at T_1 (since T_2 > T_1).

vi. This observation implies that the fraction of molecules with energies greater than E_a increases with temperature, leading to an increase in the rate of the reaction.

chapter 6. CHEMICAL KINETICS class 12 chemistry textbook solution page 137