Subject: Science
Ammonia gas is produced when nitrogenous materials degrade without oxygen, and it can be found in combination with ammonium sulphate and ammonium chloride. It is lighter than air and can be prepared in laboratories by heating a mixture of ammonium chloride and calcium hydroxide in a 2:1 ratio. The process requires equipment and chemicals, such as a lime tower and a hard glass test tube. Ammonia is colorless, smells strongly, and weighs less than air. It dissolves well in water and solidifies at -33.4°C and -78°C. It can be used in various applications, including fertilizers, plastic production, washing soda, medicines, and blue prints on maps. Ammonia is also used as a cooling agent in refrigerators and a cleaning agent to remove grease and oil from stains.
In nature, ammonia can be found in both free and mixed forms. When nitrogenous materials degrade in the absence of oxygen, this gas is created. Ammonia gas can also be found in ammonium sulphate and ammonium chloride in combination. Lavoiser had heated the ammonium chloride and calcium hydroxide mixture to produce this gas.
Symbol | Molecular weight |
NH3 | 17 |
Ammonia has a molecular weight of 17. While nitrogen has a molecular weight of 28 and carbon dioxide has a molecular weight of 44, oxygen has a molecular weight of 32. The gas is therefore lighter than the air.
In the laboratory, ammonia gas is prepared by heating the mixture of ammonium chloride (NH4CI) and calcium hydroxide [Ca(OH)2] in a ratio of 2:1 in a hard glass test tube.
Ammonium chloride + Calcium hydroxide → calcium chloride + water + ammonia
2NH4Cl (s) +Ca(OH)2(s) → CaCl2(s) + 2H2O (l) + 2NH3(g)
Apparatus Required:
Hard glass test tube, source of heat, gas jar, stand, lime tower, delivery tube, etc.
Chemicals Required:
Ammonium chloride and Calcium hydroxide
Method/ Procedure
Precautions
Test of the Gas
Physical Properties
Do you know?
Ammonia passes through the lime tower to produce pure, dry ammonia because calcium oxide absorbs moisture from ammonia.
Chemical Properties
NH3 (g) + H2O (l) → NH4 OH (aq)
NH3 (g) + HCL (aq) → NH4CL (aq) Ammonium chloride
2NH3 (g) + H2SO4 (aq) → (NH4)2SO4 (aq) Ammonium sulphate
2NH4OH (aq) + H2SO4 (aq) → (NH4)2SO4 (aq) + 2H2O (l)
NH4OH (aq) + HCL (aq) → NH4CL (aq) + H2O (l)
NH3 (g) + CO2 (g) → NH2-CO-NH2 ( s) + H2O (l)
[Urea is an important chemical fertilizer.]
4NH3 (g) + 3O2 (g) → 6H2O (l) + 2N2 (g)
4NH3 (g) + 5O2(g) → 6H2O (l) + 2NO (g)
2NH3(g) + 2Na (S) →2NaNH2 (s) + H2(g)
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