Question

How‌ ‌is‌ ‌a‌ ‌catalyst‌ ‌is‌ ‌used‌ ‌in‌ ‌a‌ ‌reaction?‌ ‌

Answer 1

Some reactions take a very long time to form a product, in such reactions suitable catalysts are used. The factor on which the catalyst affects is the activation energy. Vanadium pentoxide is a catalyst that is used in the contact process.

Complete step-by-step answer: There are many reactions that take a very long time to complete or form the product. So, to alter the time taken for the reaction we use a catalyst. Hence, a catalyst is used for the reaction to occur at a faster rate.
We know that the reaction takes place by the collision of the reactant molecules to combine to form the product. There is a certain energy in every reaction for the reactant molecule to cross, so that it can convert it into a product. This energy is known as activation energy.
For some reactions, this energy is very high and difficult to cross, so the catalyst affects this energy barrier and lowers it. When the activation energy due to the catalyst becomes low, then reactants can easily cross the activation barrier and the products will be formed at a much faster rate. There are some reactants that can even increase the rate of the reaction 10 times faster.
Some examples of catalysts are vanadium pentoxide for the contact process, iron for the Haber’s process, etc.

Note: There are some compounds that can even increase the functioning of the catalyst known as promoters, for example, molybdenum is used as a promoter for the iron in the Haber's process.