GATE 2026 MN – Question 28

Surface Environment, Mine Ventilation and Underground Hazards · Underground Hazards · 1 mark · Multiple choice

Air is79% nitrogen and21% oxygen by volume. Find methane’s volume percentage in a stoichiometric methane–air mixture.

5.4
9.5
10.8
14.8

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Show answer and explanation

Correct answer: (B) 9.5

Explanation

Complete combustion requires CH₄+2O₂→CO₂+2H₂O. One volume of methane needs2/0.21=9.5238 volumes of air. Its fraction of the total mixture is1/(1+9.5238)=0.09502, or9.5%, B. The denominator includes both methane and air.

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