2. A natural gas consisting entirely of methane (CH4) is burned with oxygen-enriched air containing 40% O2 and 60% N2. The Orsat analysis of the combustion gas shows 20.2% CO2, 4.1% O2 and 75.7% N2. What is oxygen-enriched air and why do you think it was used in combustion? Why is no CO produced? Can the Orsat analysis be correct? Show all calculations. The following reaction occurs:

CH4 + 2O2 CO2 + 2H2O