Under critical conditions, the compressibility factor for a gas is — States of Matter and Gaseous State Chemistry Question

💡 Solution & Explanation

At the critical point, evaluating the van der Waals critical constants ($P_c = a/27b^2$, $V_c = 3b$, $T_c = 8a/27Rb$) into the compressibility factor equation $Z_c = \frac{P_c V_c}{R T_c}$ directly simplifies identically to $3/8$ (or 0.375) for all van der Waals gases. Therefore, correct answer is A.