introduction
| barium hydroxide | ||
|---|---|---|
| Generally | ||
| CAS no. | 17194-00-2 (anhydrous) 22326-55-2 (H2O) 12230-71-6 (8H2O) | |
| EINECS no. | 241-234-5 | |
| Look | white solid (white is the color of a body heated to about 5000°C (see…) | |
| chemical properties | ||
| Brutal formula | H2BaO2Ba(OH)2 Ba(OH)2.H2O monohydrate Octahydrate Ba(OH)2.8H2O | |
| Mass (The term mass is used to denote two quantities attached to a …) molar | 171.342 ± 0.008 g mol-1 | |
| pKa | 14 | |
| Physical Properties | ||
| T°-Fusion (In physics and metallurgy, fusion is the transition of a body from the solid state to the …) | 681K (408°C) | |
| T° Boiling (Boiling is the formation of bubbles during a violent change in a body…) | 1053K (780°C) | |
| Density (Density is a physical quantity that characterizes the mass of a material by…) | 2.20×10³ kg/m³ (anhydrous) 3.74×10³ kg/m³ (monohydrate) | |
| thermochemistry | ||
| S0 | ~100 J/mol K | |
| ΔH0 | -945.5kJ/mol | |
| Precautions | ||
| Directive 67/548/EEC | ||
| ||
| WHMIS | ||
 D1B, D2B, | ||
| Units of the SI & CNTP unless otherwise stated (An indication (from Latin indicare: to indicate) is a written advice or recommendation…) | ||
I’barium hydroxide is a mineral compound of barium (barium is a chemical element with the symbol Ba and atomic number 56) and hydroxide ions with the chemical formula Ba(OH)2. It is a powdery white solid. It exists in two hydrated forms: monohydrate (its commercial form) and octahydrate.
Physicochemical properties
water solubility
The solubility of barium hydroxide in water (water is a ubiquitous chemical compound on earth essential to life for all…) depends strongly on temperature (temperature is a physical quantity measured with a thermometer and…). It increases with temperature from 34 g l-1 at 20 °C to 910 g l-1 at 80 °C. Barium hydroxide is therefore almost completely dissociated in water and therefore behaves like a strong base.
In the presence of carbon dioxide (carbon dioxide, commonly known as carbon dioxide or carbon dioxide, is a…) barium hydroxide reacts to form barium carbonate, which is insoluble in water:
Ba(OH)2 + CO2 → BaCO3solid + H2O
Use
Barium hydroxide is used in (chemistry is a natural science divided into several disciplines to…) analytical chemistry for titration (titrimetry or titration is a dosing technique used in analytical chemistry to…) weak acids, especially organic acids. In fact, by using a barium hydroxide solution it is possible to completely avoid the presence of carbonate ions (totally or completely automatically, or by anglicism completion or…), unlike sodium hydroxide solutions (sodium hydroxide is an ionic solid with the statistical formula NaOH. The solution resulting from…) or potassium hydroxide (potassium hydroxide, or more commonly caustic potash or simply potash,…), barium carbonate is insoluble in water. This property allows the titration to be carried out more precisely due to the absence of weakly basic carbonate ions.
Barium hydroxide is also used as a strong base in organic synthesis, for example to hydrolyze esters or nitriles.
Hydrolysis of a nitrile function
In industry it is used in particular for the production of glass and ceramics.
Preparation
Barium hydroxide is a compound that does not occur naturally. It can be made by dissolving barium oxide (BaO) in water. This dissolution produces a precipitate (In chemistry and metallurgy, a precipitate is the formation of a phase…) consisting of octahydrated barium hydroxide. The latter can be converted to barium hydroxide monohydrate by heating (heating is the transfer of thermal energy to an object,…) in the air (air is the gaseous mixture that makes up the Earth’s atmosphere. It is odorless and…) or to anhydrous barium hydroxide by heating in a vacuum (vacuum is usually defined as the absence of matter in a space zone).
It can also be made from barium sulfide (in chemistry, a sulfide is a chemical compound or the combination of sulfur with a degree…) by reaction with water:
BaS + 2H2O → Ba(OH)2 + H2S
safety and toxicity
Barium hydroxide is a strong base. It is therefore highly corrosive. In addition, like most barium compounds, it is toxic.
Hazard Statements (The Hazard Statements (“R-Phrases”) are notices on the labels of…) and Safety Advice (The Safety Statements (“S-Phrases”) are notices on the labels…)
- A: 20/21/22 (Harmful by inhalation, in contact with skin (The skin is an organ made up of several layers of tissue. It plays the role, among others…) and if swallowed)
- R: 34 (Causes burns)
- S: 26 (In case of eye contact, wash immediately, consult an ophthalmologist)
- S: 36/37/39 (Wear appropriate protective clothing, gloves and eye/face protection)
- S: 45 (In the event of an accident or if you feel unwell, seek medical advice immediately (A doctor is a healthcare professional with a PhD in…) and show the container or the label.)