Question

What is collision frequency?

Answer 1

Collision frequency:

• Collision theory was developed by Max Trautz and William Lewis in $1916-1918$.
• “According to this theory, the reactant molecules are assumed to be solid spheres and reaction is postulated to occur when molecules colloid with each other.”
• The collision frequency is defined as the average rate at which two reactants collide in the given system.
• The number of collisions per second per unit volume of the reaction mixture is known as collision frequency.

Formula of Collision frequency:

$\mathrm{Z}={\mathrm{N}}_{\mathrm{A}}{\mathrm{N}}_{\mathrm{B}}{({\mathrm{r}}_{\mathrm{A}}+{\mathrm{r}}_{\mathrm{B}})}^2\sqrt{\frac{8{\mathrm{\pi K}}_{\mathrm{B}}\mathrm{T}}{{\mathrm{\mu }}_{\mathrm{AB}}}}$

• $\mathrm{Z}$ is the collision frequency.
• ${\mathrm{N}}_{\mathrm{A}}\mathrm{and}{\mathrm{N}}_{\mathrm{B}}$are the number of A and B atoms.
• ${\mathrm{r}}_{\mathrm{A}}\mathrm{and}{\mathrm{r}}_{\mathrm{B}}$ are the radius of A and B atoms.
• ${\mathrm{K}}_{\mathrm{B}}$ is the Boltzmann constant.
• $\mathrm{T}$ is the temperature.
• ${\mathrm{\mu }}_{\mathrm{AB}}$ is the reduced mass.