Thermodynamic Systems | MCQs

Explanation

N2 (Nitrogen) has the highest critical temperature among the options (Helium - He and Hydrogen - H). 

Nitrogen (N2): While still lower than many other substances

It has a higher critical temperature than Helium because of stronger intermolecular forces. 

Explanation

Use the Gibbs free energy equation:

$$\Delta G=\Delta H-T\Delta S$$

For a process to be spontaneous, $Delta G < 0$

• If $Delta H < 0$ (exothermic)

• And $Delta S > 0$ (entropy increases)

• Then:

  $$\Delta G=\text{negative}-T\times \text{positive}=\text{always negative}$$

 So, no matter the temperature, $Delta G$ will be negative ⇒ spontaneous at all temperatures