Question

Assertion (A) Helium is used in diving apparatus.

Reason (R) Helium is very less soluble in blood.

• A. Both Assertion and Reason are correct but Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is A

Both Assertion and Reason are correct but Reason is the correct explanation for Assertion

Explanation for Correct Option:

Assertion:-

• For diving apparatus a mixture of Oxygen and Helium is used that gives the same partial pressure of ${\mathrm{O}}_2$ as in normal at 1 atm.
• Due to high partial pressure and greater solubility, ${\mathrm{N}}_2$ gets dissolved in blood and form bubbles which is very painful for the divers.
• Therefore, ${\mathrm{N}}_2$ is replaced by Helium as it is much less soluble in biological fluids.

Explanation for reason:-

• Henry's law states that the solubility of a gas in a liquid is directly proportional to the pressure of the gas.
• Helium is less soluble in blood.
• As a result for diving apparatus a mixture of Oxygen and Helium is used that gives the same partial pressure of ${\mathrm{O}}_2$ as in normal at 1 atm.
• Therefore it diffuses more rapidly and is eliminated from the blood more rapidly than nitrogen.
• Thus the reason is also true and is the correct explanation for the assertion.

Therefore, option (A) Both Assertion and Reason are correct but Reason is the correct explanation for Assertion is the correct answer.