Question

28. Select the option that correctly gives the examples
of physical and chemical changes.
Physical change Chemical change
A. Tearing of paper Breaking of glass
B. Burning of paper Cooking of food
C. Rusting of iron Melting of butter
Dr Formation of ice Burning of wood
from water​

Answer 1

Answer:

Option B. Burning of paper, cooking of food.

Explanation:

The above changes can't be reversed and are permanent.

Answer 2

Formation of ice Burning of wood from water is an example of physical and chemical changes.

Option: D

Explanation:  

• A physical process is one in which there is change of a material to other form whereas there is no change in the chemical composition of the material and which is reversible.  

• A chemical process is just the opposite of the physical process. In case of formation of ice from water the chemical composition of both water and ice is same that is $\mathrm{H}_{2} \mathrm{O}$, similarly ice can be made into water by heating it.  

• So it's a physical process. Burning of wood changes organic compounds into carbon dioxide and water vapour. Also wood cannot be obtained from these on cooling. So it is chemical process.