Question

How does a catalyst work?

Answer 1

Hint: A reaction taking place is sometimes very slow or very fast or vigorous etc. When we need to control the reactions taking place according to our wish we use catalysts and inhibitors. Catalyst is usually used to speed up the reactions and they do this by providing necessary conditions.

Complete answer:
Definition: catalyst is a substance that when added to a chemical reaction increases its rate without itself undergoing any permanent chemical change.
Inhibitors: it’s a substance that slows down or prevents the chemical reaction.
Let us see how a catalyst actually works:
The catalyst’s main function that helps to increase the rate of reaction is that it reduces the activation energy. They provide the necessary conditions for a particular reaction. They help to break bonds between some compounds and form temporary bonds with itself.
It also increases the number of particles that are able to form activated complexes .hence the rate of reaction also increases. To understand better lets take an example of enzymes as catalyst.
Enzymes are the complex nitrogenous compounds i.e. proteins produced by living plants and animals which catalyze certain biological actions. The enzymatic activity is increased in presence of co-enzymes. Its observed that when a small non-protein(vitamin) is present along with an enzyme its rate of reaction increases. In this case activators are generally metal ions such as \[N{a^ + },M{n^{2 + }},CO_2^ + ,etc.\] these metal ions weakly bond with the enzymes to help increase their catalytic activity.

Note:
In short the catalysts work by decreasing the activation energy and they decrease this energy by providing the chemical reaction a new path and new mechanism through which it can proceed. The catalyst which increases the rate of the chemical reaction are called as positive catalysts. The one that decreases the rate of the chemical reaction is called a negative catalyst.