Question

Which of the following is a physical change?
(A) Burning of coal
(B) Photosynthesis
(C) Dissolving sugar in water
(D) Digestion of food

Answer 1

Hint: To answer this question you have to understand the difference between chemical and physical change.

Complete step by step answer:
There are two types of change one is chemical change and other is physical change. A chemical change occurs due to formation and cleavage of bond in a chemical reaction and it cannot be prominently seen. Physical change is the change of matter in physical aspects such as change in quantity, colour, concentration etc. Physical change is a reversible process whereas chemical change is an irreversible process.

- Now let's look into each option
- Option A is "Burning of coal". Burning of coal is a combustion process where coal is burnt in presence of atmospheric oxygen and it is a chemical reaction and it is an irreversible process. Therefore, burning of coal is an example of chemical change. Thus, option A is an incorrect answer.
- Option B is "photosynthesis". Photosynthesis is a process in which in which it converts light energy into chemical energy .Light energy is captured from sunlight and used to convert into molecular products such as water, carbon dioxide, and minerals into oxygen and energy-rich organic compounds. It is an irreversible process. Therefore, it is an example of chemical change. Thus, option B is an incorrect answer.
- Option C is "Dissolving sugar in water". While dissolving sugar in water the colour of the water becomes blurry and concentrated. It is because no new substance is formed. Dissolving sugar in water is a reversible process as the water and sugar can be separated by different methods such as vaporization followed by condensation and crystallization. Therefore, it is an example physical change .Thus, option C is the correct answer.
- Option D is "Digestion of food". Food that breaks down into smaller substances with the help of digestive enzymes. Therefore, digestion is a chemical process and it is irreversible. Thus, option D is incorrect. So the correct answer is “C”:

Note: Chemical process is irreversible and physical process is reversible. In a chemical process reactants undergo formation or cleavage of bond in order to form products. The change in chemicals cannot be seen prominently. In the physical process no new product is formed but the change can be seen prominently in the physical aspect.