Ammonia | Chemistry for JAMB PDF Download

Laboratory and Industrial Preparations

• Ammonia is primarily prepared in the laboratory and industry through the Haber process.
• The Haber process involves the reaction between nitrogen gas (N₂) and hydrogen gas (H₂) in the presence of an iron catalyst and elevated temperature and pressure.
• The balanced chemical equation for the Haber process is: N₂ + 3H₂ → 2NH₃.

Properties and Uses

• Ammonia is a highly soluble gas in water, forming a strongly alkaline solution.
• It has a trigonal pyramidal molecular geometry, with the nitrogen atom bonded to three hydrogen atoms.
• Ammonia is lighter than air and has a density of approximately 0.771 kg/m³.
• It is a good conductor of electricity when dissolved in water due to the presence of NH₄⁺ and OH^- ions.
• Ammonia is commonly used as a refrigerant in industrial and household applications.
• It is also used as a precursor for the production of fertilizers, explosives, and various organic compounds.

Ammonium Salts and Their Uses

• Ammonium salts are compounds formed by replacing the hydrogen atoms in ammonia with various cations.
• Some common examples of ammonium salts include ammonium chloride (NH₄Cl), ammonium nitrate (NH₄NO₃), and ammonium sulfate ((NH₄)₂SO₄).
• Ammonium salts find extensive use as fertilizers, in the manufacturing of pharmaceuticals, and in the textile industry.

Oxidation of Ammonia

• Ammonia can undergo oxidation reactions to form nitrogen (IV) oxide (NO₂) and trioxonitrate (V) acid (HNO₃).
• The oxidation of ammonia to nitrogen (IV) oxide occurs when ammonia gas reacts with excess oxygen gas. The balanced equation is: 4NH₃ + 5O₂ → 4NO + 6H₂O.
• Further oxidation of nitrogen (IV) oxide with oxygen gas leads to the formation of trioxonitrate (V) acid. The balanced equation is: 2NO₂ + O₂ + H₂O → 2HNO₃.

Test for NH₄⁺

• To test for the presence of ammonium ions (NH₄⁺), a few drops of sodium hydroxide (NaOH) solution are added to the unknown solution.
• If ammonium ions are present, a pungent smell of ammonia gas will be detected.
• The gas can be further confirmed as ammonia by holding a piece of damp red litmus paper near the mouth of the test tube. If the litmus paper turns blue, it indicates the evolution of ammonia gas.
• These points provide a comprehensive overview of ammonia, its preparations, properties, uses, ammonium salts, oxidation reactions, and the test for ammonium ions (NH₄⁺).

Conclusion

In conclusion, ammonia is a versatile compound with significant laboratory and industrial applications. It is prepared through the Haber process, which involves the reaction between nitrogen and hydrogen gases. Ammonia has properties such as solubility in water, alkalinity, and conductivity when dissolved in water. It is used as a refrigerant and plays a crucial role in the production of fertilizers, explosives, and organic compounds.
Ammonium salts are derived from ammonia and find various uses in industries such as agriculture, pharmaceuticals, and textiles. The oxidation of ammonia results in the formation of nitrogen (IV) oxide and trioxonitrate (V) acid. This oxidation process occurs through a series of reactions with oxygen gas. Furthermore, the presence of ammonium ions can be tested by adding sodium hydroxide solution and detecting the release of ammonia gas, confirmed by the change in color of litmus paper.