Question

Give examples to explain the difference between changes that can or cannot be reversed.

Answer 1

Hint: We know that the reversible change is one in which a change is done physically or it can be undone that is reversed. On the other hand, the irreversible change is one in which a change is done chemically or it cannot be undone that is reversed.

Complete step by step answer:
When we change the physical state of an object, then the process is called a reversible process. Now, let’s consider some examples.
The freezing of water to make ice is a reversible process as we can get back the water by melting ice. Similarly, the distillation of liquid, sublimation of solid are reversible processes. Their corresponding reactions are shown below.
${\rm{Liquid}} \to {\rm{Vapour}}$
${\rm{Solid}} \to {\rm{Vapour}}$
Also, the glowing of an electric bulb is a reversible process. The bulb glows when we switch on the current and it turns off that it becomes dark when we switch off the current. Therefore, all these changes are reversible in nature.
However, when a change is made chemically and it cannot be reversed into its original form, then it is called an irreversible change. For example, baking a cake, burning a piece of cloth or paper. They are some irreversible changes. When a piece of cloth paper is burned, it transforms into ash. We cannot turn back ash into cloth or paper. So such processes are irreversible in nature.
Some other examples of irreversible changes include rusting of iron, making of curd with the help of milk, etc.

Note:
We can generally say that the examples of reversible changes include melting, freezing, dissolving and evaporation. Whereas heating, burning and mixing are irreversible changes.