Exams › NEET › Chemistry

50 mL of each gas A and of gas B takes 150 and 200 seconds respectively for effusing through a pin hole under the similar condition. If molecular mass of gas B is 36, the molecular mass of gas A will be:

1. 96
2. 128
3. 32
4. 64

Correct answer: 64

Solution

Using Graham's law of effusion, the rate of effusion is inversely proportional to the square root of the molar mass. The ratio of times is 150:200 (or 3:4), so the ratio of rates is 4:3. Squaring and inverting gives the molar mass ratio as 16:9. Since gas B has a molar mass of 36, gas A's molar mass is (36 × 16/9) = 64.

Related NEET Chemistry questions

• Which of the following is a true solution?
• State in which of the following examples the force of attraction between particles of matter is almost negligible.
• Dry ice is:
• Which of the following statement about Avogadro's hypothesis is correct?
• Vapour pressure of a liquid increases with :
• Who proposed that equal volumes of gases at the same temperature and pressure have same number of molecules.

⚔️ Practice NEET Chemistry free + battle 1v1 →