Consider the following statements
1. For the combustion of pulverized coal, 5 to 10% excess air is required
2. Air contains 21% oxygen by weight.
3. The flue gases from a coal- fired furnace contain around 70% nitrogen by volume.
4. In the combustion of liquid fuels, the number of moles of the products are invariably greater than the number of moles of the reactance.
Which of these statements are correct?
a) 1,2 and 4 b) 1,3 and 4
c) 2,3 and 4 d) 1 and 3