Exams › JEE Main › Chemistry

If r, P, and M denote the diffusion rate, pressure, and molecular mass respectively, then the ratio of diffusion rates of two gases A and B, rA/rB, is expressed as:

1. (P_A/P_B)(M_B/M_A)^(1/2)
2. (P_A/P_B)^(1/2)(M_B/M_A)
3. (P_A/P_B)(M_A/M_B)^(1/2)
4. (P_A/P_B)^(1/2)(M_A/M_B)

Correct answer: (P_A/P_B)(M_B/M_A)^(1/2)

Solution

The correct option is derived from Graham's law of effusion, which states that the rate of diffusion of a gas is inversely proportional to the square root of its molecular mass and directly proportional to its pressure. Therefore, the ratio of diffusion rates incorporates both the pressure ratio and the inverse square root of the molecular mass ratio.

Related JEE Main Chemistry questions

• A sample of gas has a volume of 300 cc at 27°C under a pressure of 620 mm. What will its volume be at 47°C and 640 mm pressure?
• When the temperature of neon is increased from 20°C to 40°C, by what factor does the mean kinetic energy of its atoms change?
• Which gas is expected to show the greatest departure from ideal-gas behavior?
• Equal amounts (in moles) of hydrogen gas and oxygen gas are kept in a vessel that has a tiny pinhole, allowing both gases to effuse out. By the time one-half of the hydrogen has escaped, what fraction of the oxygen has escaped?
• Which of the following statements is incorrect regarding how raising the temperature affects the distribution of molecular speeds in a gas?
• As stated by the kinetic theory of gases, how does an ideal gas molecule move during the interval between two consecutive collisions?

⚔️ Practice JEE Main Chemistry free + battle 1v1 →