Write a note on catalytic poison

Explanation

Catalytic poison: Certain substances when added to a catalysed reaction, decreases or completely destroys the activity of catalyst and they are often known as catalytic poisons.
For example, in the reaction, `2SO_(2) + O_(2) to 2SO_(3)` with a Pt catalyst, the poison is `AS_(2)O_(3)`. i.e., `AS_(2)O_(3)` destroys the activity of pt. `AS_(2)O_(3)` blocks the activity of the catalyst. So, the activity is lost.