A cylinder contains 640 gm of liquid oxygen. The volume occupied (in litres) by the oxygen, when it is released and brought to standard conditions (0°C, 760 mm Hg) will be __________ litres.

Answer: Option A

Since, every fluid at $$S.T.P$$ occupies $$22.4ltrs$$   of volume per unit mole.
Here given number of moles $$=\frac{\text{weight}}{\text{gram molecular weight}}=20$$
So, the volume occupied $$=22.4\ast 20=448ltrs.$$