Barium hydroxide, also known as baryta, is an inorganic chemical compound with the chemical formula Ba(OH)₂. It is one of the principal compounds of barium, a metallic alkaline earth metal. This compound is typically encountered in various hydrated forms, with the monohydrate and octahydrate being the most common commercial varieties.
Understanding Barium Hydroxide
Barium hydroxide is an ionic compound, consisting of positively charged barium cations (Ba²⁺) and negatively charged hydroxide anions (OH⁻). It is a strong base, completely dissociating into ions when dissolved in water. This dissociation leads to a high concentration of hydroxide ions, contributing to its strong alkaline nature.
While the anhydrous form exists, barium hydroxide commonly crystallizes as the octahydrate (Ba(OH)₂·8H₂O) or converts to the monohydrate (Ba(OH)₂·H₂O) upon heating. The white granular monohydrate is frequently used in commercial applications.
Physical and Chemical Properties
Barium hydroxide typically appears as a white solid, which can be in powder or crystalline form. Its solubility in water varies with temperature, generally increasing as the water gets hotter. For example, the octahydrate melts at 78 °C, while the monohydrate melts at 300 °C.
Chemically, barium hydroxide acts as a strong base, producing solutions with a high pH, often above 11 or even 12 when dissolved in water. This strong basicity allows it to neutralize acids, forming barium salts and water.
It also absorbs carbon dioxide from the air, forming barium carbonate as a precipitate. This property makes its clear aqueous solution useful in analytical chemistry, as it ensures the absence of carbonate impurities.
Everyday Uses and Industrial Applications
Barium hydroxide finds various uses across different industries. In analytical chemistry, it is employed for the titration of weak acids. Its clear aqueous solution is advantageous in this application because it is free of carbonate ions, which can interfere with titrations using other strong bases.
Industrially, barium hydroxide serves as a precursor for the production of other barium compounds. It is also used in:
Manufacturing lubricants and greases.
Refining sugar.
Water treatment to remove sulfates.
Production of glass and alkalis.
As a stabilizer in the plastics industry.
Safe Handling and Environmental Impact
Handling barium hydroxide requires careful attention due to its corrosive and toxic nature. As a strong base, it can cause severe irritation and burns upon contact with skin, eyes, and the respiratory tract. Inhalation of its dust or aerosols can lead to respiratory irritation, and ingestion can cause serious internal damage.
To mitigate these hazards, personal protective equipment is recommended during handling. Proper storage involves keeping containers tightly closed in a cool, dry, and well-ventilated area, separated from incompatible substances like strong acids.
Environmentally, barium compounds, including barium hydroxide, are considered toxic to aquatic life. Responsible waste management is crucial to prevent their release into water systems.