Beginner Topic 647 of 1102 Inorganic Chemistry
Ammonia
NH3 is a pungent basic gas made by the Haber process, used in fertilizers.
In-depth explanation of Ammonia
Ammonia, NH3, is a colourless gas with a sharp, pungent smell. Its trigonal pyramidal shape, with a lone pair on nitrogen, makes it polar and allows strong hydrogen bonding, so it dissolves readily in water. It is a weak base with a pKb of about 4.75 and reacts with acids to form ammonium salts. The lone pair lets ammonia act as a ligand in complexes such as the deep blue tetraamminecopper(II) ion. It is made by the Haber process, N2 + 3H2 giving 2NH3, over an iron catalyst at about 400 to 450 degrees C and 150 to 250 atm.
Going deeper: Ammonia
Key ideas: Haber process: N2 + 3H2 gives 2NH3, delta H = -92 kJ per mol. Conditions: 450 C, 200 atm, iron catalyst with K2O and Al2O3 promoters. Compromise: low temperature favors yield but slows rate. Unreacted gas is recycled and NH3 is liquefied out. NH3 is basic (Kb 1.8e-5), a ligand, and is dried with CaO, not conc H2SO4 or CaCl2. It is produced in about 150 million tonnes yearly.
Common mistakes and connections: Students think a catalyst improves the equilibrium yield; it only speeds attainment of equilibrium. Another mistake is claiming high temperature is best; yield falls with temperature, so 450 C is a rate compromise. Hydrogen comes from methane reforming. Links to Le Chatelier, equilibrium, fertilizers and nitric acid via Ostwald process.
Visualization of Ammonia
Trigonal pyramidal NH3 with a lone pair on nitrogen: this makes it polar, a hydrogen-bond donor and a weak base and ligand. The interactive lesson shows this as a live animation or chart.
Worked example and use case
Ammonia gas and hydrogen chloride gas meet to form white fumes of solid ammonium chloride.
Frequently asked questions about Ammonia
What is Ammonia?
NH3 is a pungent basic gas made by the Haber process, used in fertilizers.
Is Ammonia a beginner, intermediate or advanced topic?
Ammonia is a beginner topic in Inorganic Chemistry. It needs no earlier chemistry lessons and is a good starting point.
What should I learn before Ammonia?
Study these earlier topics in Inorganic Chemistry first: Carbon Oxides, Carbides, Nitrogen Family.
What comes after Ammonia?
The next topics in Inorganic Chemistry are Oxides of Nitrogen and Nitric Acid.
Can I practise Ammonia with quizzes?
Yes. The interactive lesson includes a self-check question on Ammonia, and the Inorganic Chemistry quiz draws on every topic in this area.
Where Ammonia fits in Inorganic Chemistry
Ammonia is topic 32 of 113 in Inorganic Chemistry.