A gaseous fuel at 25C and 15 mm Hg gage pressure is sent to a furnace at the rate of 210 m³/min and burned with 50% excess air. The fuel is composed of 10% CH₄, 4% C₃H₈, 20% H₂, 46% CO, 5% CO₂, 8% O₂, and 7% N₂. The air for combustion is at 25C and 1.1 atm.abs and has 60% relative humidity. The stack gas leaves the furnace at 400C and under a draft of 10 cm H₂O. The barometer shows 745 mm Hg. Calculate, assuming complete combustion,

a) The Orsat gas composition of the stack gas in molar percentage,

b) The dew point of the stack gas,

c) The ratio of moles of dry stack gas to the moles of dry air,

d) The volumetric flow rate of the wet stack gas in units of SCMH.