Carbon Dioxide

Carbon dioxide is a common gas that is produced from burning of fuels and exhalation of organisms. This gas was first discovered by Van Helmont  in 1630 by burning of wood. In 1783 it was proved as compound of carbon and oxygen by Lavosier. Occurrence of carbon dioxide in our atmosphere is about 0.03%. it is found on carbonate and bicarbonates of metal also.

Laboratory preparation of Carbon dioxide gas: In laboratory scale carbon dioxide is prepared by the reaction of calcium carbonate(marble Pieces) and dilute hydrochloric acid.

 CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂

 

As shown in fig above, apparatus are fitted, marble pieces on round bottom flask is covered with dilute hydrochloric acid. When chemical reaction starts carbon dioxide gas is formed and collected to gas jar. As this gas is heavier than air it is collected as liquid on gas jar(Gas jar Up).

Industrial manufacturing of carbon dioxide gas: In large scale, carbon dioxide is produce by heating lime stone(CaCO₃) in furnace. By this process calcium oxide(quick lime CaO) and carbon dioxide are produced simultaneously.

CaCO₃ → CaO + CO₂

 Physical properties of CO₂ Gas

1. It is colorless, odorless and tasteless gas
2. It is slightly soluble in water
3. It is heavier than air(about 1.5 times heavier)
4.  It is neither combustible nor supports combustion
5. Carbond dioxide freezes on -78oC  which is called dry ice
6. It is not poisonous but organisms die on its atmosphere due to displacement of oxygen

See Chemical Properties and Uses of CO₂