Explain the adsorption of nitrogen on iron.

Explanation

When nitrogen gas is brought in contact with iron at `83 K`, it is physisorbed on iron surface as nitrogen molecules `N_(2)`. As the temperature is increased the amount of introgen adsorbed decreases rapidly and at room temperature, partically there is no adsorption of nitrogen on iron. At `773 K` and above, nitrogen is chemisorbed on the surface as nitrogen atoms.