At room temperature (usually around 20-25 degrees Celsius or 68-77 degrees Fahrenheit), air cannot be compressed into a liquid solely by increasing the pressure. The reason is that at this temperature and atmospheric pressure (about 1 bar or 14.7 pounds per square inch), air exists in a gaseous state.
To convert a gas into a liquid, you need to go through a process called liquefaction, which typically involves cooling the gas to a temperature below its critical point while simultaneously increasing the pressure. The critical point is the temperature and pressure above which a gas cannot be liquified, no matter how much pressure is applied.
For air, the critical temperature is around -140.1 degrees Celsius (-220.2 degrees Fahrenheit) and the critical pressure is about 37.96 bar (550.3 pounds per square inch). To convert air into a liquid at room temperature, you would need to cool it well below the critical temperature and then apply a pressure greater than the critical pressure.
The exact pressure required to liquefy air at room temperature would depend on how much you cool the gas below its critical temperature and the specific properties of the gas. Typically, very high pressures are required, well above what can be achieved with conventional equipment. As a result, liquefying air at room temperature is not a practical task without specialized and advanced cryogenic processes and equipment.