Barium hydroxide

• Caustic baryta
• Baryta water (aq solution)

White solid

Fixed

• 4.50 g · cm -3
• 2.18 g · cm -3 ( octahydrate )

• 408 ° C
• 78 ° C ( octahydrate )

Decomposition at > 600 ° C to barium oxide and water

Soluble in water ( 72 g · l -1, octahydrate )

Risk

0.5 mg · m-3

-944.7 KJ / mol

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Barium hydroxide Ba (OH) 2 is the hydroxide of the alkaline earth metal barium. Is a strong base in aqueous solution.

Production and representation

Based on the barite ( barium sulfate) BaSO4 is obtained from barium oxide, barium hydroxide or barium: barium oxide reacts with water to barium:

Barium reacts with water to form barium hydroxide and hydrogen sulfide:

Properties

Physical Properties

Barium hydroxide is a solid, consisting of colorless crystals substance. It forms two hydrates, a monohydrate and octahydrate. The solubility in water is strongly dependent on temperature, at 20 ° C to dissolve 56 g / l of water at 80 ° C 947 g / l of water. The aqueous solution, also called baryta water is strongly alkaline, since barium hydroxide almost completely dissociated into ions. A saturated solution has a pH of 14

Chemical Properties

Barium hydroxide forms in aqueous solution with carbon dioxide or other carbonate salts a sparingly soluble precipitate of barium carbonate:

It can be used for the qualitative detection of carbonate ions.

Use

• Glass and ceramic manufacturing. Partly as a substitute for barium
• Water softening
• Used in the 18th century in connection with ammonium thiocyanate ice making, due to the highly endothermic reaction. ( Reaction is exergonic. )
• For the detection of carbon dioxide and carbonates
• The octahydrate can be used as heat storage