The critical temperature and pressure of a gas are 340 K and 42 atm, respectively. The gas can be li — States of Matter and Gaseous State Chemistry Question

💡 Solution & Explanation

A gas can only be liquefied if its temperature is at or below its critical temperature ($T \le T_c$). At $T_c = 340 \text{ K}$, a pressure of at least $P_c = 42 \text{ atm}$ is required (thus 45 atm works, 40 atm does not). Above $T_c$ (350 K), it cannot be liquefied at any pressure. Below $T_c$ (320 K), it can be liquefied at a pressure equal to or exceeding its vapor pressure at that temperature, and 42 atm will definitely be sufficient since it's higher than $P_c$. Therefore, correct answer is A,D.