Ncert Exercises & Solutions

Select the correct option based on statements below:

Assertion (A):	A liquid crystallizes into a solid and is accompanied by a decrease in entropy.
Reason (R):	In crystals, molecules organize in an ordered manner.

1.	Both (A) and (R) are true and (R) is the correct explanation of (A).
2.	Both (A) and (R) are true but (R) is not the correct explanation of (A).
3.	(A) is true but (R) is false.
4.	(A) is false but (R) is true.

Hint: A liquid crystallises into a solid and is accompanied by a decrease in entropy.

When a liquid crystallises, entropy decreases because in crystalline form the molecules are more ordered as compared to the

liquid. The movement of atoms is a solid form restricted hence, entropy decreases.

Hence, both assertion and reason are true and the reason is the correct explanation of assertion.