The composition of a gas derived by the gasification of coal is, volume percentage: carbon dioxide 4, carbon monoxide 16, hydrogen 50, methane 15, ethane 3, benzene 2, balance nitrogen. If the gas is burnt in a furnace with 20% excess air, calculate
a. the amount of air required per 100 kmol of gas,
b. The amount of flue gas produced per 100 kmol of gas,
c. the composition of the flue gases, on a dry basis.