If the volume of two gases which are kept at constant temperature and pressure below critical conditions is gradually reduced condensation will start when a certain volume is reached, the amount of condensation will gradually increase upon further reduction in volume until the gases are liquefied.
The amount of condensation will gradually increase upon further reduction in volume. The gases are liquefied. The volume of two gases is gradually reduced. These two gases are kept at constant temperature and pressure below critical conditions. Condensation will start. A certain volume is reached.