Q. The open "Sigrees" or coal stoves often require fanning to sustain burning because of:
Answer: tendency of carbon dioxide to form a layer along with dust smoke
Notes: Burning coal requires oxygen to chemically react. The availability of oxygen is limited in the furnace by several factors such as the friction of the air against the coal. Blowing provides more oxygen to the flame and raises the temperature of the flame. Besides, it helps to prevent carbon dioxide from forming carbon monoxide with dust smoke so as to keep the supply of oxygen intact.