Ammóniumhidroxidot

Ammóniumhidroxidot, commonly known as ammonium hydroxide, is an aqueous solution of ammonia in water. It is often represented by the formula NH3·H2O or NH4OH, though in solution the chemical equilibrium NH3 + H2O ⇌ NH4+ + OH− describes its basic character. In practice, ammonium hydroxide refers to relatively dilute solutions of ammonia in water rather than a discrete solid compound.

Preparation and composition are tied to the dissolution of ammonia gas in water. Industrially, ammonia gas is absorbed into water to form a solution that can be adjusted to desired strengths, with typical household solutions containing several percent ammonia by weight. Concentrated solutions may approach about 25–30% NH3 by weight at room temperature, and their composition is in dynamic equilibrium with dissolved ammonia gas.

Properties of ammonium hydroxide include being a colorless, pungent-smelling liquid that is highly miscible with water. The solution is a weak base, producing hydroxide ions in solution and giving a high pH (typically around 11–12 for household formulations). It readily reacts with acids to form ammonium salts and can act as a reagent in various organic and inorganic syntheses. It is volatile, releasing ammonia gas, especially when concentrated or heated.

Uses span cleaning and pH adjustment, where it serves as a base and nitrogen source. It is employed in agriculture for fertilizer production, in metalworking and mining for pH control, and as a precursor in the manufacture of various ammonium salts and organic compounds. It can also be used in titration as a standard base.

Safety considerations include its caustic and irritating nature to skin, eyes, and respiratory tract. It can form toxic chloramines and chlorine gas when mixed with oxidizers such as bleach (sodium hypochlorite). Adequate ventilation, eye and skin protection, and storage away from acids and oxidizers are recommended.