Question

3. CONCEPT BASE
correct the following sentences by changing one word in the sentences
a) Products obtained on complete combustion are carbon dioxide and carbon monoxide.
b) Solid fuels are cleaner fuels.
c) Blue zone is the zone of incomplete combustion.
d) Fire extinguisher uses oxygen to control and extinguish fire.
e) LPG, kerosene, petrol, dry leaves and paper have a high ignition temperature.
f) When a candle burns the wax acts as a combustible material.
g) Charcoal is obtained by the fractional distillation of an organic substance.
h) CNG, LPG and biogas are examples of smoky fuels.​

Answer 1

Answer:

(a) During complete combustion carbon and hydrogen combine with oxygen (O2) to produce carbon dioxide (CO2) and water (H2O). During incomplete combustion part of the carbon is not completely oxidized producing soot or carbon monoxide (CO).

(C) Blue zone:

This is the initial and found at the base of the flame. Just at the base we will notice the blue hue. At this stage there is incomplete burning of carbon dioxide thus resulting in formation of carbon monoxide. This flame is usually used for heating as the temperature is more at this zone.

(d) Most fire extinguishers work by separating the fuel from the oxygen. The oxygen comes from the air. It is the same oxygen we breathe. Since the oxygen has to be in contact with the fuel, if you can coat the fuel with something that keeps the oxygen away, the fire will go out.

(h) CNG and LPG are clean fuels and do not gives smoke when burnt therefore used as an alternative to petrol and diesel. CNG and LPG have high calorific value and they can be transported easily through pipelines as they can be easily distributed by pressurizing and pumping.