NEET Physics: change of state Practice Questions
15 free multiple-choice questions on change of state (Properties of Solids and Liquids) for NEET Physics, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more NEET questions in the app →Q1. Which state of matter generally has the highest compressibility among solids, liquids, and gases?
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Correct answer: B — Plasma
Gases are highly compressible because they have large intermolecular spaces, allowing significant volume reduction when pressure is applied. Solids and liquids are nearly incompressible.
Q2. Which state of matter has the least intermolecular force of attraction among the three states of matter (solid, liquid, gas)?
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Correct answer: B — Gas
In the gaseous state, the molecules are far apart and move randomly with the least constraint, thus having the weakest intermolecular forces compared to the ordered structure of solids and the intermediate forces of liquids.
Q3. The temperature at which the vapor pressure of a liquid equals the surrounding atmospheric pressure is known as the boiling point. What happens to the vapor pressure of a liquid when it is heated above its boiling point?
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Correct answer: B — It increases
Above the boiling point, the liquid turns into a gas (vaporization), causing its vapor pressure to increase significantly.
Q4. What is the temperature at which the solid and liquid phases of a substance coexist in equilibrium?
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Correct answer: C — Triple point
The triple point is the unique temperature and pressure at which all three phases (solid, liquid, and gas) coexist in thermodynamic equilibrium.
Q5. Which of the following statements correctly describes the change in volume when water changes from liquid to gas (vaporization)?
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Correct answer: A — Volume increases because molecules occupy more space.
When water vaporizes, the gaseous state occupies a much larger volume than the liquid state, causing a significant increase in volume.
Q6. During the process of boiling, the change in state from liquid to gas occurs at a specific temperature known as the boiling point. What happens to the kinetic energy of the molecules during this process?
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Correct answer: A — It increases
To change from a liquid state to a gaseous state, energy must be absorbed to overcome intermolecular forces, thus increasing the average kinetic energy of the molecules.
Q7. Which of the following processes involves the absorption of heat by the substance without any change in its temperature?
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Correct answer: A — Boiling
Boiling (vaporization) and condensation (liquefaction) are endothermic processes that occur at constant temperatures (boiling point/condensation point). This is the definition of latent heat absorption.
Q8. Which of the following statements is true regarding the liquid-gas equilibrium of a substance at a constant temperature?
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Correct answer: D — The vapor pressure of the liquid is equal to the equilibrium vapor pressure of the gas phase.
At a constant temperature, the system is at equilibrium. For a liquid to coexist with its vapor in equilibrium, the vapor pressure exerted by the liquid must be equal to the equilibrium vapor pressure of the gas phase above it.
Q9. Which process involves the absorption of heat by a substance to change its state from solid to liquid?
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Correct answer: B — Melting
Melting is the process where a solid absorbs heat energy and changes into a liquid state at its melting point.
Q10. If the pressure exerted on a gas is increased while keeping its volume constant (isochoric process), what happens to the internal energy of the gas?
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Correct answer: D — Internal energy increases
For an ideal gas, internal energy depends only on temperature. If volume is constant, and assuming the process is reversible or adiabatic with specific constraints, the state change implies a change in energy related to pressure work, leading to an increase in internal energy if external work is done.
Q11. Which substance has the highest compressibility among the gases listed below at the same pressure and temperature?
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Correct answer: C — Carbon Dioxide
Compressibility is inversely related to the molecular mass/size. Carbon dioxide (M ≈ 44 g/mol) is generally the most compressible among the common diatomic and triatomic gases listed under standard conditions.
Q12. At a given pressure, the vapor pressure of a liquid is directly proportional to the temperature. This relationship is described by which law?
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Correct answer: D — Raoult's Law
Raoult's Law relates the vapor pressure of a liquid in equilibrium with a gas above it to the mole fraction of the liquid, and implicitly relates vapor pressure to temperature.
Q13. When water freezes into ice, the overall potential energy of the system changes. Is this process endothermic or exothermic?
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Correct answer: A — Endothermic
Freezing (solidification) is a process where the system releases energy to the surroundings; therefore, it is an exothermic process.
Q14. During the melting of a substance at its equilibrium temperature, the change in the system's internal energy is primarily related to which concept?
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Correct answer: B — Increase in potential energy
Melting involves the absorption of energy (latent heat) to break intermolecular bonds, which increases the potential energy of the system.
Q15. The process where a solid directly changes into a gas without passing through the liquid state is known as:
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Correct answer: A — Sublimation
Sublimation is the direct transition from the solid phase to the gaseous phase.
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