Calculate the mass of air required to burn per \(\mathrm{kg}\) of coal for chimney height of \(40 \mathrm{~mm}\). Draught produced is \(24 \mathrm{~mm}\) of water. The temperature of flue gas inside the chimney is \(350^{\circ} \mathrm{C}\) and that of the air outside the chimney is \(20^{\circ} \mathrm{C}\). Also, calculate the drought produced in term of hot flue gas column.