Directions: The next items consist of two statements, one labeled as the ‘Assertion (A)’ and the other as ‘Reason (R)’. You are to examine these two statements carefully and select the answer to these items using the code given below:
(a) Both A and R are individually true and R is the correct explanation of A.
(b) Both A and R are individually true but R is not the correct explanation of A.
(c) A is true but R is false
(d) A is false but R is true
Assertion (A) : A mixture of gaseous air in equilibrium with liquid air is a pure substance.
Reason (R) : A pure substance has a homogeneous and invariable chemical composition.