To an evacuated vessel with movable piston under external pressure of 1 atm 0.1 mole of He and 1.0 mole of an unknown compound vapour pressure 0.68 atm at `0^(@)C` are introduced Considering the ideal gas behaviour the total volume (in litre) of the gases at `0^(@)C` is close to .

Answer

7

Explanation

For an ideal gas, `PV = nRT`
`3He = 0.1, P = 1 atm - 0.68 = 0.32`
`:. 0.32 xx V = 0.7 xx 0.0821 xx 273`
`:. V = 9`