Two cylinders, both fitted with frictionless pistons, are filled with mixtures of He and Ar gases. In the first cylinder, the masses of He and Ar are and , respectively. In the second cylinder, the masses of He and Ar are and , respectively. The molar mass of Ar is 10 times the molar mass of He. The external pressure applied by the piston on the first cylinder needs to be 5 times that on the second cylinder so that the volume of the gas mixtures in both the cylinders are equal at the same temperature. Assuming He and Ar behave like ideal gases, the value of is ____.
← JEE Advanced 2026 · Paper 1
ChemistryNumerical+4Question 41 of 48
JEE Advanced 2026 · Paper 1, Chemistry question 9
Answer and worked solution
Official answer: 9.8
Let be the molar mass of He, so Ar has .
Moles.
- Cylinder 1: .
- Cylinder 2: .
Same and , so and :