Calcium hydroxide
From Wikipedia, the free encyclopedia
| Calcium hydroxide | |
|---|---|
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| General | |
| Systematic name | Calcium hydroxide |
| Other names | Calcium(II) hydroxide, slaked lime, hydrated lime. |
| Molecular formula | Ca(OH)2 |
| Molar mass | 74.093 g/mol |
| Appearance | Soft white powder. |
| Crystal Structure | hexagonal |
| CAS number | [1305-62-0] |
| Properties | |
| Density and phase | 2.24 g/cm3, solid |
| Solubility in water | 0.185g/100 cm3 Ksp = 4.68 × 10−6 |
| Melting point | 580°C (Decomposes). |
| Boiling point | N/A |
| Basicity (pKb) | N/A |
| Specific Heat Capacity | 1.18095 J/g-°C |
| Heat of formation | -985.2 kJ/mol |
| Hazards | |
| MSDS | External MSDS |
| EU classification | Corrosive (C) |
| R-phrases | R34, R36, R37, R38, R41. |
| S-phrases | S22, S26, S39, S45. |
| NFPA 704 | N/A |
| Flash point | Non-flammable. |
| Supplementary data page | |
| Structure and properties |
n, εr, etc. |
| Thermodynamic data |
Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| Related compounds | |
| Other anions | None listed. |
| Other cations | None listed. |
| Related bases | Calcium oxide. |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Calcium hydroxide is a chemical compound with the chemical formula Ca(OH)2. It is a colourless crystal or white powder, and is created when calcium oxide (called lime or quicklime) is slaked with water. It can also be created by mixing an aqueous solution of calcium chloride and an aqueous solution of sodium hydroxide. A traditional name for calcium hydroxide is slaked lime, or hydrated lime.
If heated, calcium hydroxide decomposes into calcium oxide and water. A suspension of fine calcium hydroxide particles in water, called lime water (or milk of lime), is a medium strength base that reacts violently with acids and attacks many metals in presence of water.
[edit] Uses
Because of its strong basic properties, calcium hydroxide has varied uses, such as:
- A form of lime, in water and sewage treatment and improvement of acid soils
- An ingredient in whitewash, mortar, and plaster
- An alkali used as a lye substitute in no-lye hair relaxers
- A chemical depilatory agent found in Nair
- A reagent
- In the reef aquarium hobby for adding bio-available calcium in solution for calcium-using animals such as algae, snails, hard tube worms, and corals (often referred to as Kalkwasser mix)
- In the tanning industry for neutralization of extra acid
- In the petroleum refining industry for the manufacture of additives to oils (alkilsalicatic, sulphatic, fenatic)
- In the chemical industry for manufacture of calcium stearate
- In the food industry for processing water (for alcoholic and soft drinks)
- For clearing a brine of carbonates of calcium and magnesium in the manufacture of salt for food and pharmacopoeia
- In Native American and Latin American cooking, calcium hydroxide is called "cal." Corn cooked with cal becomes nixtamal, which is considered tastier and easier to digest.
- A filler
- In the petrochemical industry for manufacturing solid oil of various marks
- In the manufacture of brake pads
- In the manufacture of ebonite
- For preparation of dry mixes for painting and decorating
- In manufacturing mixes for pesticides
- In manufacturing a drug called "Polikar" for fighting decay (due to fungus) of fruits and vegetables during storage
- A dressing in paste form used for anti-microbial effect during a dental root canal procedure.[1]
[edit] Health risks
An overdose of calcium hydroxide can have dangerous symptoms, including:
- Difficulty in breathing
- Internal bleeding
- Hypotension
- Skeletal muscle paralysis, interferance with actin-myosin system.
- An increase in blood pH, which is damaging to the internal organs.
