JEE Main202311 Apr 2023Morning ShiftPhysicsKinetic Theory of GasesActual
Three vessels of equal volume contain gases at the same temperature and pressure. The first vessel contains neon (monoatomic), the second contains chlorine (diatomic) and third contains uranium hexafluoride (polyatomic). Arrange these on the basis of their root mean square speed v r m s and choose the correct answer from the options given below:
Options
- Av r m s ( mono ) > v r m s ( dia ) > v r m s ( poly )
- BV r m s ( mono ) = V r m s ( dia ) = V r m s ( poly )
- Cv r m s ( mono ) < v r m s ( dia ) < v r m s ( poly )
- Dv r m s ( dia ) < v r m s ( poly ) < v r m s ( mono )
Correct answer
A. v r m s ( mono ) > v r m s ( dia ) > v r m s ( poly )
Step-by-step solution
The RMS speed is given v r m s = 3 R T M . The temperature and pressure is same for all the gases. So the speed is inversely proportional to the square root of the molar mass of the gases. v r m s ( m o n o ) = 3 R T 4 × 10 - 3 v r m s ( d i a ) = 3 R T 71 × 10 - 3 v r m s ( p o l y ) = 3 R T 352 × 10 - 3 v rms  ∝ 1 M Hence, v r m s ( p o l y ) < v r m s ( d i a ) < v r m s ( m o n o ) .