ammonia

Ammonia is a colorless gas with a characteristic pungent odor. Its chemical formula is NH3, and the molecule has a trigonal pyramidal shape with a lone electron pair. At standard conditions it boils at −33.3 °C and freezes at −77.7 °C. It is highly soluble in water, forming ammonium hydroxide (NH4OH) in solution, which is a weak base.

In nature and industry, ammonia plays a central role. It occurs in trace amounts in the atmosphere and is produced biologically during nitrogen cycling. Industrially, ammonia is produced primarily by the Haber-Bosch process, which combines nitrogen from the air with hydrogen (from natural gas or water) over an iron catalyst at high pressure and temperature to yield NH3.

Ammonia is a key feedstock and intermediate in many processes. The largest share of produced ammonia is used to manufacture nitrogenous fertilizers, such as ammonium nitrate, urea, and ammonium phosphates. It is also employed as a refrigerant (R-717) in industrial systems, as a cleaning agent, and as a precursor for various nitrogen-containing compounds and explosives.

Chemically, ammonia acts as a weak base in water: NH3 + H2O ⇌ NH4+ + OH−. It readily forms ammonium salts with acids and forms complexes with certain metal ions, serving as a ligand in coordination chemistry.

Safety and environment: ammonia can irritate the eyes, skin, and respiratory tract; exposure at high concentrations can be hazardous and corrosive. It is toxic to aquatic life in sufficient concentrations. Proper ventilation, handling protocols, and adherence to exposure limits are important in workplaces and during transport.

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