The compressibility of a gas is less than unity at STP. Therefore — States of Matter and Gaseous State Chemistry Question

💡 Solution & Explanation

I need to see the options to explain why B is correct. However, I can provide the reasoning for compressibility less than unity: **Compressibility Factor ($Z$):** The compressibility factor is defined as: $$Z = \frac{PV}{nRT}$$ When $Z < 1$ at STP, this means: $$PV < nRT$$ **Physical Interpretation:** - $Z < 1$ indicates **attractive intermolecular forces dominate** over repulsive forces - The gas occupies **less volume than predicted by ideal gas law** - Real volume < ideal volume at the same P and T **Common Conclusion (likely option B):** This typically means: - **Attractive forces between gas molecules are significant** - The gas **deviates negatively from ideal behavior** - Molecules are pulled closer together than ideal gas assumptions predict **Why other interpretations are wrong:** - If $Z > 1$: repulsive forces dominate (volume larger than ideal) - If $Z = 1$: gas behaves ideally - $Z < 1$ ≠ "gas is more compressible" (actually less compressible due to attraction) Without seeing option B explicitly, the key takeaway is: **$Z < 1$ at STP means intermolecular attractive forces are dominant**, causing the real gas to deviate negatively from ideal behavior. Please share the options for a complete answer.