Answer:the fractional conversion of methane is 12.5%
Explanation:The reaction represent the combustion of methane to produce Co2 and steam.
CH4 +2O2_CO2 + 2H2O
From gay lussac law of proportionality
1mol of CH4 requires 2mol of Oxygen to produce 1 mol of CO2 and 2mol of H2O
So from the combining ratio,25% of O2 will fractional produce 25×1/2% of CH4.
While 12.5% of CO2 and 25% of steam is also produced .so in essence 2.5% of CO2 was lost in the reaction.