van der Waal's constants and the corresponding values of critical temperature for three gases P, Q a — States of Matter and Gaseous State Chemistry Question
Question
van der Waal's constants $b$ and the corresponding values of critical temperature for three gases P, Q and R, are given below <br><br>Gas | Critical temperature | van der Waal's constant $b$<br>P | –200°C | 0.03 l/mol<br>Q | –100°C | 0.02 l/mol<br>R | +50°C | 0.01 l/mol<br><br>Which of the gases are liquefiable at a temperature –110°C by application of increasing pressure?
💡 Solution & Explanation
A gas can only be liquefied if the ambient temperature is below its critical temperature ($T \le T_c$). For $T = -110^\circ\text{C}$: Gas P ($T_c = -200^\circ\text{C}$) cannot be liquefied since $-110 > -200$. Gas Q ($T_c = -100^\circ\text{C}$) and Gas R ($T_c = +50^\circ\text{C}$) both have $T_c > -110^\circ\text{C}$, so they can be liquefied. Therefore, correct answer is C.