BaOH2

Barium hydroxide, with the chemical formula Ba(OH)2, is an inorganic compound that appears as a white solid. In common use it exists as hydrates, most notably Ba(OH)2·8H2O, which readily hydrates from the atmosphere and can lose water upon heating to give the anhydrous form. The solid is highly soluble in water, and solutions are strongly alkaline.

In aqueous solution, Ba(OH)2 dissociates to form Ba2+ and OH− ions, making it a strong base. The solid and its hydrates are caustic and can cause severe chemical burns. On exposure to carbon dioxide, Ba(OH)2 reacts to form insoluble barium carbonate and water: Ba(OH)2 + CO2 → BaCO3↓ + H2O. It also reacts with acids to give the corresponding barium salts and water.

Production and forms: Ba(OH)2 is typically prepared by reacting barium oxide (BaO) with water: BaO + H2O → Ba(OH)2. The compound is highly hygroscopic and readily forms hydrates; heating hydrates can yield anhydrous Ba(OH)2, which is also deliquescent.

Applications: Ba(OH)2 is used as a strong base in chemical synthesis, laboratory titrations, and pH adjustment. Its solutions can absorb CO2 in certain processes, and barium salts derived from Ba(OH)2 are employed in various industrial applications; however, handling must consider toxicity and solubility.

Safety: Barium hydroxide is corrosive and toxic due to the Ba2+ ion. It should be handled with appropriate protective equipment, using gloves and eye protection, in a well-ventilated area. Avoid ingestion or inhalation of dust or solutions, and store away from acids and moisture in sealed containers.

See also: Barium compounds; Hydroxides