Carbondioxide

When coal, wood, kerosene, lard, oil, wax, etc. burn and combine with the air, carbon dioxide is created. Along with volcanic eruptions and the decomposition of organic materials, this gas is also created during the respiration processes of plants and animals. By volume, atmospheric air has a carbon dioxide content of around 0.03%. Fuel combustion and deforestation are two artificially created sources of carbon dioxide in the atmosphere. By burning wood, Van Helmont found carbon dioxide around 1630 AD. In a similar manner, Joseph Black burned magnesium carbonate to create this gas in 1755 AD. Lavoisier subsequently demonstrated that carbon dioxide gas is a mixture of carbon and oxygen.

Laboratory Preparation of Carbon Dioxide Gas

In a laboratory, diluted hydrochloric acid (dil. HCl) and limestone (CaCO₃) combine chemically to produce carbon dioxide gas.

Calcium Carbonate + dilute Hydrochloric acid → Calcium chloride + water + carbon dioxide

CaCO₃(s) + 2HCL (aq)→ CaCl₂ (aq) + H₂O (l) + CO₂ (g)

Apparatus Required

Thistle funnel, delivery tube, rubber cork, gas jar, Wolfe's bottle, and a few test tubes.

Chemicals Required

Eggshells, diluted hydrochloric acid, phenolphthalein, lime water, sodium hydroxide solution, marble or limestone pieces, calcium carbonate powder, and blue litmus paper.

Method/ Procedure

• Gather the equipment and materials needed to prepare the gas.
• Keep adding egg shells, marble, limestone, or calcium carbonate powder to the Woulfe's bottle.
• Insert the delivery tube into one of the Woulfe's bottle's apertures and the delivery tube into another, sealing them shut with rubber corks. As indicated in the illustration, insert the delivery tube and thistle funnel into the aperture of Wolfe's bottle and tighten the cork to create an airtight seal.
• Use the thistle funnel to pour diluted hydrochloric acid into the Woulfe's bottle until it covers the egg shells, limestone, marble pieces, calcium carbonate powder, or any combination of these. The thistle funnel's entrance should be inside the acid layer.
• Permit the gas to flow through the delivery tube and gather in the upright gas jar.
• Watch how the acid and calcium carbonate react.
• During the process, carbon dioxide is produced, and the gas travels through the delivery tube from Woulfe's bottle to the gas jar. Because this gas is heavier than air, the upward displacement of air collects it in the gas jar.

Precautions

• Avoid dipping the delivery tube's end into the acid.
• Dip the end of the thistle funnel into the acid.

Test of Gas

• In the case of a carbon dioxide test, a blazing match extinguishes as it gets close to the gas jar's opening because carbon dioxide is neither flammable nor conducive to combustion.
• A moist blue litmus turns blue when it comes in contact with the carbon dioxide-filled gas jar's mouth. Similar to this, the gas jar stays colorless or unaltered when a few drops of phenolphthalein are added. This demonstrates that carbon dioxide is the gas present in the gas jar.
• After passing carbon dioxide through a small amount of lime water in a test tube for a while, the water turns milky white. The reason for this is because the carbon dioxide and calcium hydroxide in the lime water combine to generate insoluble calcium carbonate. The production of soluble calcium bicarbonate is the reason behind the disappearance of the milky white color after prolonged carbon dioxide exposure.
  
  Ca(OH)₂(aq) + CO₂(g) → CaCO₃(s) (milky) + H₂O(l)
  CaCO₃(s) + CO₂(g) + H₂O(l) → Ca(HCO₃)₂(aq) (colorless)

Properties of Carbon Dioxide Gas

Physical Properties

• It is a colorless, odorless oxide that is acidic or non-metallic.
• This gas has a sour flavor because it dissolves in water to generate carbonic acid.
• It dissolves slightly in water.
• Compared to air, it is 1.5 times heavier.
• It turns wet blue litmus paper red and exhibits acidic qualities.
• Although this gas is harmless, organisms in carbon dioxide environments die from oxygen deprivation from a shortage of oxygen gas.
• It is convertible to a liquid at low temperatures and high pressures.
• Dry ice, or carbon dioxide, is the solid state that results from cooling carbon dioxide below -78°C.
• This gas does not promote burning and is not combustible.

Chemical Properties

• Carbon dioxide is not flammable or conducive to burning. It aids in putting out the fire. However, if burning magnesium is put into a jar containing carbon dioxide, it burns brilliantly and releases both black and white carbon powder and magnesium oxide (MgO) powder. This demonstrates the carbon in CO₂.

2Mg (S) + CO₂ (g) → 2MgO (S) + C (g)

• Carbonic acid is created when carbon dioxide is dissolved in water. To give soft drinks a sour flavor, this gas is added under high pressure.

CO₂ (g) + H₂O (L) ⇄ H₂CO₃ (aq)

• Lime water turns milky white when carbon dioxide gas is introduced and stays there for a while because insoluble calcium carbonate is formed.
                                                  Ca(OH)₂ (aq) + CO₂ (g) → CaCO₃ (s) + H₂O (l)
  Similarly, the creation of soluble calcium bicarbonate [Ca(HCO₃)₂] causes the milky white color to disappear when this gas is introduced to lime water for an extended period of time.

CaCO₃ (s) + H₂O (l) + CO₂ (g) → Ca (HCO₃)₂ (aq)

• The level within a test tube filled with CO₂ and submerged in water rises when a few drops of KOH are introduced. As KOH absorbs CO₂, low pressure is created inside the test tube, causing water to rush into it.

2KOH + CO₂ → K₂CO₃+ H₂O

• To produce their food in the form of carbohydrates, green plants react the carbon dioxide from the air with the water their roots absorb in the presence of sunlight.

6CO₂ + 6H₂O \(\frac {solar\:energy}{chlorophyll}\) C₆H₁₂O₆ + 6O₂

• At 900°, carbon dioxide and red-hot coke combine to make carbon monoxide.

CO₂+ C → 2CO

Uses of Carbon Dioxide Gas

• High pressure is used to dissolve carbon dioxide in soft drinks.
• Carbon dioxide is a basic ingredient that plants need to make food.
• Fire is put out with the help of this gas. A fire extinguisher is the tool used to put out fires. Typically, the cylinder is filled with a concentrated sodium bicarbonate solution. Near the extinguisher's mouth, a glass bottle with a plunger attached holds a strong solution of sulfuric acid. Sulfuric acid and sodium bicarbonate combine when the plunger is pulled, producing carbon dioxide that shoots out at a fast rate of speed and covers the fire with a thick blanket. This will cause an oxygen shortage, which will put out the fire.
  
                             2NaHCO₃ + H₂SO₄ → Na₂SO₄ + 2H₂O + 2CO₂
• Dry ice, which is used to preserve fruits, vegetables, meat, etc. in colder climates, is made with carbon dioxide.
• Sugar is purified in sugar mills using liquid carbon dioxide through the carbonation process.
• It is also used to prepare urea (NH₂CONH₂), washing soda (Na₂CO₃), and baking soda (NaHCO₃).
• Carbogen is made with it. 95% oxygen and 5% carbon dioxide make up carbogen. For artificial respiration, patients with pneumonia are treated with carbogen.
• Green plants use carbon dioxide for photosynthesis.
                    6CO₂ + 6H₂O + \(\frac {solar\:energy}{chlorophyll}\) C₆H₁₂O₆+6O₂
• It is a component of baked goods.