MCQ Collection
Pakistan MCQs
Practice Pakistan questions with answers and explanations.
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Correct Answer: A. PV = nRT
Explanation:
The ideal gas equation combines several gas laws.
It relates pressure, volume, amount, and absolute temperature.
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Correct Answer: A. 3.0 L
Explanation:
Use V1/T1=V2/T2.
V2=2.0×450/300 = 3.0 L.
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Correct Answer: B. At low pressure and high temperature
Explanation:
Low pressure keeps particles far apart.
High temperature reduces the relative importance of attractions.
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Correct Answer: B. 200 kPa
Explanation:
Use P1/T1=P2/T2.
P2=100×600/300 = 200 kPa.
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Correct Answer: C. Pressure a gas would exert alone in the mixture volume
Explanation:
Dalton's law treats each ideal gas independently.
Total pressure is the sum of partial pressures.
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Correct Answer: C. 0.987 mol
Explanation:
Use n=PV/RT.
N=100×24.6/(8.31×300)≈0.987 mol.
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Correct Answer: D. Spontaneous mixing caused by random particle motion
Explanation:
Particles move from regions of higher concentration toward lower concentration.
Diffusion occurs in gases, liquids, and solids.
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Correct Answer: D. 100 kPa
Explanation:
Dalton's law adds partial pressures.
20+35+45 = 100 kPa.
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Correct Answer: A. Escape of gas through a tiny opening
Explanation:
Effusion rates depend on molar mass.
Lighter gases generally effuse faster.
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Correct Answer: A. 1.0 mol
Explanation:
Moles equal molarity times volume in liters.
0.50×2.0 = 1.0 mol.
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Correct Answer: B. A solid with long-range ordered particle arrangement
Explanation:
Crystalline solids have repeating lattice structures.
They often have sharp melting points.
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Correct Answer: B. The part of the universe chosen for study
Explanation:
The system may be a reaction mixture, gas, or other selected matter.
Everything else is called the surroundings.