Question

Which of the following is/are true according to Maxwell - Boltzmann Statistics and Arrhenius Theory ?

• A. When temperature is raised, the maximum of the curve moves
  to the higher energy value.
• B. When temperature is raised, the maximum of the curve moves
  to the lower energy value.
• C. When temperature is raised, the fraction of molecules which collide with energies greater than activation energy increases.
• D. When temperature is raised, the fraction of molecules which collide with energies greater than activation energy decreases.

Answer 1

Answer: (A), (C)

When temperature is raised, the fraction of molecules which collide with energies greater than activation energy increases.

Maxwell - Boltzmann Statistics and Arrhenius Theory
All molecules in the reacting species do not have the same kinetic energy. It is difficult to predict the behaviour of any one
molecule with precision.So statistics is used to predict the behaviour of a large number of molecules.

The distribution of kinetic energy may be described by plotting the fraction of molecules $\left(N_E/N_T\right)$ with a given kinetic energy $\left(E\right)$ vs. kinetic energy.
Where,
$N_E$ is the number of molecules with energy $E$
$N_T$ is total number of molecules.

When temperature is raised, the maximum of the curve moves
to the higher energy value. Curve broadens out with greater proportion of molecules with much higher energies.


When temperature is raised, the fraction of molecules which collide with energies greater than activation energy increases.
Arrhenius equation :
$k=A{e}^{-\frac{E_a}{RT}}$
where,
$e^{-\frac{E_a}{RT}}$: The fraction of molecules that have kinetic energy greater than $E_a$