Balance combustion to find oxygen needs Steps:

• General combustion: CxHyOz + (x + y/4 - z/2) O2 → x CO2 + (y/2) H2O
• For 3 carbons, O2 required = 3 + y/4 - z/2 = 4.5
• Compute y and z for each option's formula
• Identify match to 4.5 O2 Why D is correct:
• Propan-1-ol (C3H8O) balances as C3H8O + 4.5 O2 → 3 CO2 + 4 H2O, matching the oxygen requirement Why the others are wrong:
• A. Propane (C3H8): requires 5 O2 (C3H8 + 5 O2 → 3 CO2 + 4 H2O)
• B. Propanoic acid (C3H6O2): requires 3.5 O2 (C3H6O2 + 3.5 O2 → 3 CO2 + 3 H2O)
• C. Propanone (C3H6O): requires 4 O2 (C3H6O + 4 O2 → 3 CO2 + 3 H2O)

Final answer: D