Which of the following statement(s) is/are correct?

All statements are correct.

The critical temperature of a substance is the temperature at and above which, the vapour of the substance cannot be liquefied, no matter how much pressure is applied. So, the higher critical temperature of a gas will lead to a higher extent of adsorption.

Freundlich adsorption isotherm fails at high pressure of the gas being adsorbed since it becomes independent of pressure.

In colloidal and surface chemistry, the critical micelle concentration (CMC) is defined as the concentration of surfactants above which micelles form and all additional surfactants added to the system go to micelles. Due to the longer hydrophobic chain, attraction forces decreases and CMC is smaller.

The Gibb's free energy of adsorption is negative at the beginning of adsorption as it is a spontaneous process.