8. Assertion : The concept of surface tension is held only for liquids. Reason : Surface tension does not hold for gases.

Read the assertion and reason carefully to mark the correct option out of the options given below:

(a)       If both assertion and reason are true and the reason is the correct explanation of the assertion.

(b)       If both assertion and reason are true but reason is not the correct explanation of the assertion.

(c)        If assertion is true but reason is false.

(d)       If the assertion and reason both are false.

(e)       If assertion is false but reason is true.

Ans. (b) We know that the intermolecular distance between the gas molecules is  large as compared to that of liquid. Due to it the forces of cohesion in the gas molecules are very small and these are quite large for liquids. Therefore, the concept of surface tension is applicable to liquid but not to gases.