Balancing combustion equations for oxygen requirement

Steps:

• Use combustion formula for CxHyOz: CxHyOz + (x + y/4 - z/2)O2 → xCO2 + (y/2)H2O, with x=3.
• For propane (C3H8, z=0): O2 = 3 + 8/4 - 0 = 5.
• For propanoic acid (C3H6O2): O2 = 3 + 6/4 - 2/2 = 3.5.
• For propanone (C3H6O): O2 = 3 + 6/4 - 1/2 = 4; for propan-1-ol (C3H8O): O2 = 3 + 8/4 - 1/2 = 4.5.

Why D is correct:

• Propan-1-ol (C3H8O) requires exactly 4.5 O2 molecules per the balanced combustion equation.

Why the others are wrong:

• A: Propane (C3H8) requires 5 O2 molecules.
• B: Propanoic acid (C3H6O2) requires 3.5 O2 molecules.
• C: Propanone (C3H6O) requires 4 O2 molecules.

Final answer: D