Catalysts

Catalysts

When we hear the word catalyst, the first thing that comes to mind is the game “Mirror’s Edge Catalyst”. But actually, catalysts are chemical substances that speed up the process of a chemical reaction but do not used up in the process of speeding up. The process of using catalysts to speed up chemical processes is called catalysis.

Some examples are:

Ø Hydrogen peroxide decomposes to form water and oxygen.

2H2O2 à 2H2O + O2

But in the presence of manganese dioxide (MnO2) the process is sped up and happens a lot faster.

Ø Cars use a catalytic converter to convert carbon monoxide to carbon dioxide. These contain Platinum to speed up the process and keep the car’s system getting backed up.

Ø Ammonia synthesis also uses Iron as a catalyst

Catalysts work by reacting with a reactant. This is called a catalytic action. The product of the catalytic action is a chemical intermediate, which can react with the other reactant at a faster pace and give us the desired end product. While this is happening, the catalyst is regenerated. It can be better explained as follows:

A + B à P

(This is reaction, A and B are reactants, forming product P)

First,

A + Catalyst à D

(One reactant reacts with the catalyst to form a chemical intermediate, D)

D + B à P + Catalyst (regenerated)

(D reacts with the other reactant to form product P and catalyst used up is regenerated)

NOTE: The chemical equations are not written so.

Solid catalysts are usually either metals, or the halides, sulphides or oxides of the metals. They are also usually of the semimetallic elements such as Boron, Silicon and Aluminium. Liquid catalysts and gaseous catalysts are used in their pure forms or with carriers or as solvents, but solid carriers require a catalyst supports to be dispersed.

We can represent catalytic activity with the letter ‘z’. The SI un it for measuring catalytic activity is mol/s. It is otherwise known as 1 katal or 1 kat. 1 kat = 1 mol/s. It is defined as the amount of the catalyst (represented in moles) to convert 1 mole of the net reactants to the desired product in 1 second or simply put, to make the speed of the net reaction 1 mole per second. However there are some incidents when the katal cannot be calculated accurately. Chemical substances known as poisons or inhibitors can slow down the net reaction speed and substances called promoters can increase the speed of the reaction.

All in all, catalysts are amazing. They can speed up chemical reactions and open us to a brand new range of chemical substances. Catalysts are already being used in industries to increase the rate of production to save time. The world has already moved on to catalysts, and therefore we must learn about them too.



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