Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R. In the light of the above statements, choose the correct answer from the options given below:
- Both A and R are true but R is NOT the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
- Both A and R are true and R is the correct explanation of A.
Answer
(2) A is true but R is false.
Solution
A is true: a mixture of helium and oxygen is used in diving apparatus in place of air.
R is false: helium is used because of its very low solubility in blood (unlike N2, it does not dissolve in blood under high pressure, so it avoids 'bends'); its solubility in O2 is not the reason.
Answer: (2)