×375=75mL Volume of air =375−75=300mL Total volume of gases after combustion = vol. of CO2+ vol. of air =330mL Volume of CO2=330−300=30mL 15mLCxHy gives =30mLCO2 1mLCxHy gives =
30
15
=2mLCO2 At constant T and P; Volume ∝ mole ∴1molCxHy=2molCO2 x=2 (
4x+y
4
)=
75
15
4x+y=20 y=20−4×2=12 Hence, formula of the hydrocarbon is C2H12.