Relevant Titles
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Liquefaction and Deviation from Ideal Gas Class 11 Chemistry MCQs
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CBSE Class 11 Chemistry Quiz – States of Matter: Liquefaction & Real Gas Behavior
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NCERT-Based MCQs on Liquefaction and Real Gases for Class 11 Students
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Online Practice Test: Class 11 Chemistry – Liquefaction and Deviation from Ideal Gas
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CBSE Class 11 Physical Chemistry Questions – Real Gases and Liquefaction Concepts
📘 Introduction
Understanding the liquefaction of gases and the deviation from ideal gas behavior is essential in mastering Chapter 5 — States of Matter: Gases and Liquids from the CBSE Class 11 Chemistry syllabus. These topics explain why real gases differ from ideal gases under certain conditions of temperature and pressure. The process of liquefaction forms the foundation for industries dealing with air separation, refrigeration, and gas storage.
This online MCQ practice test covers key concepts such as critical temperature, van der Waals equation, compressibility factor (Z), and Joule–Thomson effect, helping students reinforce their conceptual clarity. Each multiple-choice question follows the NCERT textbook pattern, designed to test both theoretical and numerical understanding.
These Class 11 Chemistry MCQs are ideal for CBSE board exam preparation and competitive tests like JEE and NEET. Attempt the quiz to check your progress, improve accuracy, and strengthen your foundation in Physical Chemistry.
🧪 Sample MCQs (with Answers and Explanations):
Q1. What does the critical temperature of a gas represent?
A) The temperature above which gas cannot be liquefied by pressure alone
B) The temperature below which all gases liquefy
C) The freezing point of a gas
D) The boiling point at 1 atm
✅ Answer: A
💡 Explanation: Critical temperature (Tc) is the temperature above which a gas cannot be liquefied, no matter how high the pressure is.
Q2. In the van der Waals equation, the constant ‘a’ corrects for:
A) Molecular volume
B) Intermolecular attractions
C) Pressure
D) Temperature
✅ Answer: B
💡 Explanation: The term a accounts for intermolecular attractions between gas molecules, which reduces the observed pressure.
Q3. When Z (compressibility factor) < 1, it indicates:
A) Ideal behavior
B) Predominant repulsive forces
C) Predominant attractive forces
D) No deviation from ideality
✅ Answer: C
💡 Explanation: A Z value less than 1 means attractive forces dominate, reducing the product PV compared to an ideal gas.
Q4. Which law or equation describes the behavior of real gases more accurately than PV = nRT?
A) Dalton’s Law
B) Graham’s Law
C) Van der Waals Equation
D) Charles’s Law
✅ Answer: C
💡 Explanation: Van der Waals equation modifies the ideal gas law by including corrections for molecular volume (b) and attraction (a).
Q5. What is the significance of the Joule–Thomson effect in gas liquefaction?
A) It causes gases to expand without cooling
B) It produces cooling during expansion under constant enthalpy
C) It increases gas pressure
D) It heats gases for liquefaction
✅ Answer: B
💡 Explanation: The Joule–Thomson effect is used in gas liquefaction; gases cool during throttling at constant enthalpy, enabling condensation.