Catalysis

In chemistry, what is the definition of a catalyst

Catalysts are described in chemistry as chemicals that modify the rate of a reaction by altering the process’s course. In other words, they alter the reaction’s trajectory. The bulk of the time, a catalyst is used to speed up or raise the reaction rate. Catalysts are used to either break or repair chemical bonds between the atoms of different elements or compounds that are present in their respective molecules, according to a deeper level of examination. Catalysts are molecules that urge molecules to react, making the whole process easier and more efficient.

A Quick History of the Past

Catalysts, in their broadest sense, are anything that speeds up the pace at which a process happens. Chemist Elizabeth Fulhame was the first to examine the concept of catalysis, which she presented in her book in 1794, more than a century later. Her study on oxidation-reduction experiments inspired the material of this book.

Gottlieb Kirchhoff, a Russian chemist of German descent, discovered the first chemical reaction in organic chemistry that required the use of a catalyst in 1811 and published his findings the following year. In 1835, a Swedish chemist named Jöns Jakob Berzelius coined the term “catalysis” to describe reactions that were accelerated by the presence of certain substances. In addition, the substances remained unchanged as a result of the reaction.

Examples of Catalysts of Different Types 

There are many different types of catalysts that can be used in a chemical reaction, depending on the need or requirement of the reaction. Since a catalyst is used to speed up a particular reaction in an equilibrium, therefore the following are some examples:

Catalysts for the Positive

Positive catalysts are catalysts that speed up the rate at which a chemical reaction occurs. It accelerates the rate of reaction by lowering the activation energy barriers, allowing a greater number of reaction molecules to be converted into products, thereby increasing the percentage of product yield. An example of a positive catalyst: If you use the Haber’s process to make ammonia, iron oxide acts as a positive catalyst, increasing the yield of ammonia even though there is less reaction of nitrogen with the nitrogen.

Catalysts with a Negative Effect

Catalysts that slow down a reaction are called negative catalysts. As the activation energy barrier increases, the number of reactant molecules that can be converted to products decreases, and as a result, the reaction rate slows down and eventually stops. To illustrate a negative catalyst, consider the following: When acetanilide is used, the decomposition of hydrogen peroxide to water and oxygen is retarded. Acetanilide acts as a negative catalyst, slowing the rate at which hydrogen peroxide breaks down into water and oxygen. 

Conclusion

In a catalysed process, the catalyst is usually chemically reacted with the reagents, but finally regenerates, so the catalyst level remains constant. Since the catalyst is not consumed, each catalyst molecule can cause the conversion of a large number of reactant molecules. The number of molecules that have changed every minute from a single active catalyst molecule can be up to several million.