example:
The chemical reaction of mercuric chloride (HgCl2) and oxalic acid is slow. The reaction of acidic potassium permanganate (KMnO4) and oxylic acid is faster than the above reaction.
If the vessel containing the first chemical reaction is mixed with some amount of acidic potassium permanganate (KMnO4), then the speed of the first chemical reaction also increases.
Here the chemical reaction of potassium permanganate (KMnO4) and oxalic acid induces chemical reaction of mercuric chloride and oxalic acid, which increases its speed. This phenomenon is an example of induced catalysis.