Carbon dioxide

Carbon dioxide is 0.03 percent of the total volume of air. This gas is produced by burning of fuel, by respiration and by rotting of animals and plants (vegetables) and is added to the atmosphere.

The concentration of this gas remains constant (fixed) in the atmosphere, as it is used by plants in the process of photosynthesis.


  1. Carbon dioxide is used in fire extinguishers.
  2. Dry ice is also called dry carbon dioxide, which is used for refrigeration.
  3. Carbon dioxide is also used in cold beverages.


The presence of carbon dioxide can be determined by the following tests:

  1. When carbon dioxide gas flows into lime water, its color becomes milky.
  2. When a burning stick is taken to a jar filled with carbon dioxide, carbon dioxide does not help its combustion process like a firefighter.