When 2 gm of a gas A is introduced into an evacuated flask kept at 25°C, the pressure is found to be 1 atmosphere. If 3 gm of another gas B is then added to the same flask, the total pressure becomes 1.5 atmospheres. Assuming ideal gas behaviour, the ratio of molecular weights, MA ∶ MB will be
1
1 ∶ 3
2
3 ∶ 1
3
2 ∶ 3
4
3 ∶ 2