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From Wikipedia

Calcium hydroxide

Calcium hydroxide, traditionally called slaked lime, is an inorganic compound with the chemical formula Ca(OH)2. It is a colourless crystal or white powder and is obtained when calcium oxide (called lime or quicklime) is mixed, or "slaked" with water. It has many names including hydrated lime, builders lime, slack lime, cal, or pickling lime. It is of low toxicity and finds many applications.


When heated to 512 °C, the partial pressure of water in equilibrium with calcium hydroxide reaches 101 kPa, which decomposes calcium hydroxide into calcium oxide and water.

Ca(OH)2→ CaO + H2O

A suspension of fine calcium hydroxide particles in water is called milk of lime. The solution is called lime water and is a medium strength base that reacts with acids and attacks many metals in presence of water. Lime water turns milky in the presence of carbon dioxide due to formation of calcium carbonate:

Ca(OH)2 + CO2→ CaCO3 + H2O

Calcium hydroxide crystallizes in the same motif as cadmium iodide. The layers are interconnected by hydrogen bonds.

Preparation and occurrence

Calcium hydroxide is produced commercially by treating lime with water:

CaO + H2O → Ca(OH)2

In the laboratory it can be prepared by mixing an aqueous solutions of calcium chloride and sodium hydroxide. The mineral form, portlandite, is relatively rare but can be found in some volcanic, plutonic, and metamorphic rocks. It has also been known to arise in burning coal dumps.


One significant application of calcium hydroxide is as a flocculant, in water and sewage treatment. It forms a fluffy charged solid that aids in the removal of smaller particles from water, resulting in a clearer product. This application is enabled by the low cost and non-toxicity of calcium hydroxide. It is also used in fresh water treatment for raising the pH of the water so that the pipes won't corrode where the base water is acidic. The reason is that it's self regulating and does not raise the pH too much.

Another large application is in the paper industry, where it is used in the production of sodium hydroxide. This conversion is a component of the Kraft process.

Niche uses

Because it is produced on a large scale, is easily handled, and is cheap, myriad niche and even large scale applications have been described. A partial listing follows:

  • An ingredient in whitewash, mortar, and plaster
  • To fill the root canal for the first stage of endodontic therapy (it is then replaced by rubber).
  • As an additive to sea water to reduce atmospheric CO2 and mitigate the greenhouse effect.
  • In the production of metals, lime is injected into the waste gas stream to neutralize acids, such as fluorides and chlorides prior to being released to atmosphere.
  • An alkali used as a lye substitute in no-lye hair relaxers
  • A chemical depilatory agent found in most hair removal creams (for example Nair)
  • In Bordeaux mixture to neutralize the solution and form a long lasting fungicide
  • In the petroleum refining industry for the manufacture of additives to oils (salicatic, sulphatic, fenatic)
  • In the chemical industry for manufacture of calcium stearate

Food industry

Because of its low toxicity and the mildness of its basic properties, it is widely used in the food industry and associated hobbies: Examples:

  • The separation of sugar from sugar cane in the sugar industry
  • For processing water for alcoholic beverages, soft drinks.
  • Used in the processing of Norwegian lutefisk.

From Yahoo Answers

Question:i know acetic acid is CH3OOH and calcium hydroxide is Ca(OH)2 but im not sure what is formed... i was thinking CaCO3 and water but i dont know what else. i have to write the molecular equation, total ionic, and net ionic.

Answers:This is an acid base reaction. Like all simple acid base reactions (those between a Bronsted-Lowry base and a Bronsted-Lowry acid), the products will be water and a salt of the acid. In this case, that salt will be calcium acetate, Ca(CH3COO)2: Molecular: 2CH3COOH + Ca(OH)2 -----> 2H2O + Ca(CH3COO)2 Because acetic acid and calcium hydroxide can both be supplied in pure form, they do not need to be split into component ions (and acetic acid is a weak acid anyway, so we would not need to do this): Complete ionic: 2CH3COOH + Ca(OH)2 -----> 2H2O + Ca2+ + 2CH3COO- The net ionic would only be different if we started with a solution of Ca(OH)2 rather than the solid. In this case: Complete ionic: 2CH3COOH + Ca2+ + 2OH- -----> 2H2O + Ca2+ + 2CH3COO- Net ionic: CH3COOH + OH- -----> H2O + CH3COO- Because Ca(OH)2 is a strong base, this reaction will proceed nearly completely.

Question:Complete the following acid-base reaction with a molecular, total ionic and net ionic equation. calcium hydroxide(aq) + acetic acid(aq) --> ?

Answers:Ca(OH)2 + 2 CH3COOH = Ca(CH3COO)2 + 2 H2O calcium acetate + water

Question:Include subscripts and or up down arrows Molecular: 2HC2H3O2 (AQ) + Ca(OH)2 ----> CA(C2H3O2)2 +2H2O

Answers:Molecular equation for reaction between CH3COOH and Ca(OH)2 2CH3COOH(aq) + Ca(OH)2(aq) (CH3COO-)2Ca(aq) + 2H2O (l) Write the full ionic equation by separating all compounds that dissociate into ions: anything (s), (g) or (l) does not dissociate 2CH3COO- (aq) + 2H+(aq) + Ca2+(aq) + 2OH - (aq) 2CH3COO- (aq) + Ca2+(aq) + 2H2O(l) Write the NET ionic equation: inspect the fullionic equation above and delete anthing which is identical on both sides of the sign In this case that is 2CH3COO- (aq) + Ca2+(aq) to be deleted. What is left is the net ionic equation: Net iopnic equation: 2H+(aq) + 2OH-(aq) 2H2 (l) simplify: H+(aq) + OH-(aq) H2O (l).

Question:I have tried a million different answers and the program won't accept them. Please help

Answers:Overall reaction: 2CH3COOH(aq) + Ca(OH)2(aq) --> Ca(CH3COO)2(s) + 2H2O(l) Net Ionic Equation: Ca^+2(aq) + 2CH3COO-(aq) + H+(aq) + OH-(aq) --> Ca(CH3COO)2(s) + H2O(l)