Chemical Change: Reversible & Irreversible Changes

An Introduction

One material can be transformed into another with differing qualities as a result of a chemical transformation. One or newer substances are likely to form in this environment. Synthesis or breakdown of two substances might lead to a new substance being formed as a result of this process. The oxidation reaction is one example of a chemical change that results in a chemical reaction. 

Chemical reactions are normally irreversible, except in the case of reversible alterations in chemistry. Some instances of chemical alterations are the creation of dye in the colour and the chemical change in the colour of hair.  

Chemical Changes 

It is possible for a chemical alteration to be reversed, or it is not. Let's take a closer look at them.   

Reversible Change 

The term "reversible change" refers to a chemical alteration that can be undone. One or more approaches can be used to undo this alteration. Only the physical qualities of the material, such as its size and shape, tend to change in a reversible alteration. In the vast majority of circumstances, new material is not created when a chemical reaction is reversible. The elongation of a spring or the folding of paper are two examples of reversible chemical changes. 

Irreversible Change 

An irreversible change is a change that cannot be reversed by any physical or chemical methods. Newer substances are formed when a substance undergoes a permanent change. 

Reversible and irreversible alterations both have their merits and disadvantages. The blacksmith, for example, can cast a piece of iron into a variety of shapes. Following the heating procedure, the iron piece is pounded to the appropriate shape. Metals expand when heated and compress when cooled, as we know. In light of this, it is clear why we see reduced spaces between rails on the railway lines. In the summer, the temperature rises, causing the metal tracks to expand. Consequently, these gaps in the train lines compensate for the increase in the area. 

Chemical Process:  

  \[Hydrogen(H_{2})+Oxygen(O_{2}) \rightarrow Water(H_{2}O)\] 

(Image Will be Uploaded Soon)


A chemical process is depicted in this diagram. hydrogen gas (2 H-H) is combined with oxygen gas (O=O) to form two molecules of water in the reaction (2 H-O-H). In the diagram, look at the arrow. What message does it convey? There is a strong correlation between the direction of the reaction and the formation of water.

FAQs (Frequently Asked Questions)

1. What is a Chemical Change?

A chemical reaction occurs when two or more components combine to generate a new substance known as chemical synthesis or chemical breakdown. We refer to these processes like chemical reactions since there is no way to reverse them except by undergoing additional chemical reactions.

2. Explain Chemical change with an example.

The chemical properties of water are not altered as the ice melts to become water; hence this is a purely physical transformation. A lot of people don't know this, but water can be frozen again extremely quickly. Hydrogen is released when water combines with an alkaline metal. Water and alkaline metal, which were the reactants, do not appear in the result. On the other hand, products are wholly new substances that are distinct from the reactants in their composition.

3. What are Irreversible changes?

An irreversible change is one that is permanent and cannot be reversed through physical or chemical means. When a substance goes through an irreversible alteration, it tends to generate fresh substances.

4. What are Reversible Changes?

A reversible chemical change is one that can be reversed. This modification can be reverted using one or more procedures. Only the physical qualities of the material, such as its size and shape, tend to change in a reversible alteration. In most circumstances, new material is not created when a reversible chemical reaction occurs. Examples of reversible chemical changes include spring elongation, paper folding, and so on.

5. Write a few examples of Chemical changes you see in your daily life?

Chemical changes occur all the time and are a part of our daily lives. Some instances of chemical reactions that occur in our daily lives are given below: 


  1. Burning of log of wood and paper

  2. Cooking an egg

  3. Digestion of food

  4. Chemical battery use

  5. Baking a cake

  6. Electroplating of a metal

  7. Milk turning sour

  8. Rotting of fruits

  9. Several metabolic reactions take place in the body cells

  10. Decomposition of the waste

  11. Reaction between acids and salts

  12. Fireworks explosion 

  13. Lightening a matchstick

  14. Metal rusting

6. Are Chemical Changes Reversible?

Chemical changes generally result in newer substances and hence cannot be undone. Consider, for example, the burning of logs. We cannot change the ashes from these burnt logs back into the wood. 

Some of the chemical changes can be reversed,  but only when there are other chemical changes. Consider, for example,  undoing the tarnish on copper pennies. You can do so when you place them in vinegar.  The acid in the vinegar tends to combine with the copper oxide from the tarnish. This, in turn, changes the copper oxide back to Oxygen and copper, making the pennies reddish-brown in colour again.

Hence we can say that chemical changes can only be reversed when other chemical changes are occurring further.