Question

Statement I: At the same temperature lighter gas molecules have a higher average velocity than heavier gas molecules.
Statement II: At the same temperature lighter gas molecules have a higher average kinetic energy than heavier gas molecules.

• A. Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1
• B. Both the Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation of Statement 1
• C. Statement 1 is correct but Statement 2 is not correct
• D. Statement 1 is not correct but Statement 2 is correct
• E. Both the Statement 1 and Statement 2 are not correct

Answer 1

Answer: (C)

Statement 1 is correct but Statement 2 is not correct

Statement I: At the same temperature lighter gas molecules have a higher average velocity than heavier gas molecules.
At the given temperature average velocity is inversely proportional to the square root of molecular weight.
Statement II: At the same temperature lighter gas molecules have same average kinetic energy as heavier gas molecules.
The average kinetic energy is directly proportional to the absolute temperature but it is independent of the molecular weight.
The average kinetic energy per molecule $=\frac{3}{2}kT$
Statement 1 is correct but Statement 2 is not correct.