Question

Which of the following is a chemical change?
(A) Boiling of eggs
(B) Evaporation of water
(C) Precipitation of snow
(D) Melting of wax

Answer 1

we need to first understand what exactly a chemical change means. Now a chemical change is one which cannot be reversed and also after the chemical reaction gets completed a new product is formed.

Complete answer:
First of all we all need to understand what a reaction is. A reaction is defined as the process by which two substances or once a substance goes through some changes. These reactions can be further divided into physical reactions and chemical reactions. Physical reactions involve the molecular rearrangement of the atoms. Here the molecules are not altered chemically but a physical change is observed.
N0ow in a chemical change what happens is that one or two products are heated or mixed together and kept in some vessel for them to react. Now in a chemical reaction what happens is a new product is formed and the product that is formed cannot be reversed back to the original reactants of the reactions.
In the above question we are given various processes.
Now in evaporation of water, the water can be cooled down, therefore, can be reversed and not a chemical change.
Next, we have precipitation of snow, now here the snow or water can be easily heated and converted to its liquid state, therefore the process is reversible and not a chemical change.
The same goes for the melting of wax.
But what happens in the boiling of egg is that the egg’s protein on getting heated gets converted repentantly in texture and also in appearance and therefore cannot be reversed and it is a chemical reaction.
Hence the required answer is Boiling of egg is a chemical reaction.

Note:
Now the chemical reaction is also further divided into various parts on the basis of properties of the chemical reaction. The various forms of the chemical reaction are combination reactions. Decomposition reaction, displacement reaction and so on.