NEET2020Physics-Kinetic Theory of Gases
NEET 2020 Physics Ideal Gas Law and Density MCQ Question
Type: MCQ-numerical-Medium-Class 11
A cylinder contains hydrogen gas at pressure of 249 kPa and temperature 27°C. Its density is: (R = 8.3 J mol⁻¹ K⁻¹)
A
0.1 kg/m³
B
0.02 kg/m³
C
0.5 kg/m³
D
0.2 kg/m³
Correct Answer
Option D
Detailed Explanation
Using the ideal gas law: PV = nRT, and density ρ = PM/(RT), where M is molar mass. For hydrogen gas (H₂), M = 2 × 10⁻³ kg/mol. P = 249 kPa = 249 × 10³ Pa, T = 27°C = 300 K, R = 8.3 J mol⁻¹ K⁻¹. ρ = (249 × 10³ × 2 × 10⁻³)/(8.3 × 300) = 498/2490 = 0.2 kg/m³. The correct answer is D.
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