First, we require the combustion equation of propane:
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
We see that each mole of propane produces 4 moles of water.
Now, we calculate the moles of water required: 75 / 18.02
Moles required = 4.16
Moles of propane required for this are: 4.16 / 4 = 1.04 moles
Each mole of gas occupies 22.14 liters, so the volume of propane required are 1.04 * 22.14 = 23.03 L
23 L of propane are required
