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GATE 2020 CE (CE1) – Question 63

Air Pollution and Municipal Solid Wastes · Air pollution: pollutants, sources, impacts, control and air quality index · 2 marks · Numerical answer

A gas concentration is 41.6 μmol/m³ at 1 atm and 293 K. With $R=82.05\times10^{-6}$ m³·atm/(mol·K) and ideal gas behavior, find concentration (ppm), to one decimal.

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Correct answer: .9 to 1.1

Explanation

Ideal-gas air molar concentration is p/(RT). Gas mole fraction is $41.6\times10^{-6}RT/p$. Multiplying by one million gives $ppm=41.6(82.05\times10^{-6})(293)=1.000088$. **1.0 ppm**.