Can we liquify gases by applying pressure or reducing temperature ?

A gas can be liquefied by pressure alone when its temperature is

Consider following statements : (A): The gas whose critical temperature is above room temperature can be liquified by applying sufficient pressure to the gas. (B): The gas whose critical temperature is below room temperature can be liquified by the temperature below T_c . Select correct statement

For a given mass of gas, if pressure is reduced to half and temperature is increased two times, then the volume of gas would become ___ times .

The essential conditions for liquefaction of gases were discovered by Andrews in 1869 as a result of his study of pressure-volume-temperature relationship for CO_(2) . It was found that above a certain temperature, it was impossible to liquefy a gas whatever the pressure was applied. The temperature below which the gas can be liquefied by the application of pressure alone is called critical temperature (Tc). The pressure required to liquefy a gas at this temperature is called the critical pressure (Pc). The volume occupied by one mole of the substance at the critical temperature and pressure is called critical volume. Critical constants are related with van der waals' constant as follows: V_( c) = 3b, P_( c) =a/(27b^(2)), T_( c) =(8a)/(27 Rb) The values of critical volumes of four gases A, B, C and D are 0.025L, 0.312L, 0.245L and 0.432L respectively. The gas with larger molecular diameter will be :

(A) : For a constant volume gas thermometer one should fill the gas at high temperature and low pressure. ( R) : Many of the properties of gases are common at low pressures and high temperatures.

The temperature above which a gas cannot be liquified even on application of high pressure is called

The temperature above which a gas cannot be liquified even on application of high pressure is called