What Is Barium Hydroxide?
Barium hydroxide, a basic inorganic compound of barium, primarily exists as a monohydrate (92-95%) in its dry form and as colorless octahydrate crystals in aqueous solution. Known as baryta water when dissolved, it is strongly alkaline and can react with carbon dioxide in the air to form barium carbonate. Due to its high toxicity, similar to other soluble barium compounds, it is regulated as a deleterious substance.
Uses of Barium Hydroxide
Its applications span from glass manufacturing, oil refining, and water softening to sugar manufacturing, producing various barium compounds, and organic synthesis. Barium hydroxide is also utilized in the saponification of fats and oils, as a stabilizer for grease and vinyl chloride, and as an analytical reagent in laboratories for titrations and carbon dioxide determination. It’s used for creating catalysts, lubricant additives, pigments, plating reagents, and for melting silicates.
Properties of Barium Hydroxide
This white crystalline compound is characterized by its ease of solubility in water and methanol, with a melting point of 408°C for the anhydride, 78°C for the octahydrate, and decomposition at 780°C. It appears granular or powdery, with a molecular weight of 171.34 and the chemical formula Ba(OH)2. The anhydride has a monoclinic crystal structure, while the octahydrate is tetragonal. The densities for the anhydride, monohydrate, and octahydrate are 4.495 g/cm3 and 3.74 g/cm3, respectively.
Other Information on Barium Hydroxide
1. Synthesis Methods
Barium hydroxide is produced through the hydration of barium oxide, yielding octahydrate upon recrystallization and monohydrate when heated in air. Anhydride formation occurs at 100°C under reduced pressure. The reaction of barium nitrate with sodium hydroxide also produces barium hydroxide octahydrate.
2. Titration Applications
Used for titrating weak and organic acids in analytical chemistry, barium hydroxide’s solution clarity is due to its lack of carbonate, allowing for accurate endpoint determination in titrations with phenolphthalein or thymolphthalein as indicators.
3. Decomposition Reactions
As a strong base, it is employed in organic synthesis for ester and nitrile hydrolysis, including selective hydrolysis in specific organic compounds, and neutralizing acidic spills.
4. Synthetic Reactions
Barium hydroxide facilitates the synthesis of cyclopentanone, diacetone alcohol, and D(-)-gulonic acid γ-lactone, showcasing its versatility in chemical reactions.