Learn The Concepts Based On Reducing Agents

What is a reducing agent?

A reducing agent in the language of chemistry is any element or a certain compound that can lose or donate its electrons.

A reducing agent is sometimes referred to as an electron donor, reductant or a reducer in any chemical reaction.

We all must have studied redox reactions in our chemistry classes. Any reaction where oxidation and reduction occur simultaneously is also known as a Redox reaction.

Oxidation is referred to as a state where the loss of electrons occurs. A reduction is referred to as a state where the gain of electrons occurs.

What is the definition of oxidation, reduction, oxidisers and reducers?

Usually, when one studies oxidation and reduction, one feels that all oxidation, reduction, oxidisers and reducers are the same. But they are different.

An oxidiser is an agent that gets oxidized by the loss of electrons.An oxidizing agent is an agent that can gain electrons and reduce itself.

What is a reducing agent?

A reducing agent is an agent that is capable of reducing another substance.A reducing agent is an agent that can lose its electrons and gets oxidised itself.

Redox reaction

In a typical redox reaction, oxidation and reduction happen simultaneously.In any reaction in chemistry, there is a method to differentiate between an oxidizing agent and a reducer.

Let’s learn how to identify a reducing agent and an oxidizing agent.

When we observe the species whose oxidation state is increasing in a reaction, it means that it is losing or donating its electrons. That species is identified as a reducing agent or a reducer. On the other hand, if there is any reaction, one observes that a species whose oxidation state is decreasing, then it means that it is gaining or receiving the electrons. This particular species is known as an oxidiser or an oxidizing agent.

Thus, one can conclude that a reducing agent gets oxidized by another agent, and an oxidizing agent gets reduced by another agent.Before any reaction takes place, there is a pre-reaction state observed in all the species participating in any reaction.

A reducing agent in a reaction is commonly observed to have extra electrons. That is why they can get reduced themselves.

An oxidizing agent in a reaction is observed to lack electrons. They need electrons. That is why they can get oxidized themselves.

A reducing agent is known to be present in its lowest oxidation state, having extra electrons with it. That is why it tends to donate electrons to the nearby species. The best examples of Reducing agents are:

• Earth metals

• Acids such as formic acid, oxalic acid etc.

• The sulphite compounds found

Due to this property, it is also known to be an electron donor.

History of Reduction and Reducing agents

The history of reduction goes back to when the Great Oxidation event took place.

To the early atmosphere of earth, a species of biologically produced oxygen was added, which acted as an oxidiser. The primitive atmosphere of the Earth is considered to be reducing.

It was considered to be a reducing atmosphere as it was assumed to be composed of gasses like methane (CH4), Carbon dioxide (CO2), along with all the other reducing agents found in the atmosphere.

As no oxygen was found, the extra electrons could not be used up. The cyanobacteria in the primitive atmosphere used the water molecule to form oxygen. Oxygen got formed as its waste product. Gradually and steadily, the oxygen got added up to the atmosphere. It exceeded the amount of reducing agents present in the atmosphere, which led it to become an oxidizing atmosphere. 

Characteristic of a reducing agent

The strong reducing agents are the agents that can lose electrons fast and easily.

An atom with a large atomic radius is considered a good reducing agent. The electrons in these types of species have a larger distance between the nucleus and their electrons in the valence shells, which makes the attraction poorer. Such types of elements are thought to be good reducing agents.

A good reducing agent has the following properties:

1. Low electronegativity because the distance between the nucleus and their valence electrons is large, so very little attraction is observed.
2. Small ionization energies 

A negative reduction potential means that the species is a strong reducing agent. A positive reduction potential means that the species is a weak reducing agent. The reduction potential is observed from the electrochemical series.

Lithium (Li) is the strongest reducing agent in the periodic table of elements. It is considered the strongest reducing agent because of its highest negative potential. It can donate the extra electrons present in it easily.

Conclusion

Reducing agents find their importance in corrosion, polygeneration systems in iron and steel making, gas-fired power plants etc.