Carbon Dioxide II

 Chemical Properties of CO₂ gas.

1.  Carbon dioxide reacts with potassium hydroxide to form potassium carbonate

       2KOH + CO₂ → K₂CO₃ + H₂O

2.  Carbon dioxide is not combustible but magnesium ribbon keeps on burning on its environment to form magnesium oxide and carbon is released.

       2Mg + CO₂ → 2MgO + C

3. If carbon dioxide is sent to clear lime water it turns mlky white due to formation of insoluble calcium carbonate

      Ca(OH)₂ + CO₂ → CaCO₃ + H₂O

But if CO₂ is passed for long time it again turns to colourless due to formation of soluble calcium bicarbonate

      CaCO₃ + CO₂ + H₂O → Ca(HCO₃)₂

4. Plants use carbon dioxide with water in presence of chlorophyll to make glucose

      6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

5. When carbon dioxide is heated with hot red coke at 900^oC, carbon monoxide is formed.

      CO₂ + C → 2CO

6. Carbon dioxide when dissolved with water, carbonic acid is formed.

      CO₂ + H₂O → H₂CO₃

Uses of CO₂ gas

1. To prepare beer, soda water and cold drinks

2. To prepare food by plants during photosynthesis

3. It is used as fire extinguisher in offices and industries 

For the quick formation of CO2 gas, baking soda powder and concentrated sulphuric  acid are kept separately, when need for fire extinction, they are mixed by hitting the system and reaction takes place

2NaHCO₃ + H₂SO₄ → Na₂SO₄ + 2H₂O + CO₂

4. Liquid carbon dioxide is used in sugar mill for carbonation

5. Solid carbon dioxide also called dry ice is used to keep fruits, vegetable and meat fresh.

6. CO₂ is used for making Urea(NH₂CONH₂), a chemical fertilizer and washing soda(Na₂CO₃)