Lime water
Encyclopedia
Limewater is the common name for saturated
calcium hydroxide
solution
. It is sparsely soluble. Its chemical formula is Ca(OH)2. Since calcium hydroxide is only sparsely soluble, i.e. ca. 1.5 g per liter at 25 °C, there is no visible distinction to clear water(homogeneous). Attentive observers will notice a slightly earthy smell. It is clearly distinguishable by the alkaline taste of the calcium hydroxide. The term lime refers to the mineral
, rather than the fruit
. When exposed with carbon dioxide
, lime water turns into a milky solution.
While limewater is a clear solution, milk of lime on the other hand is a suspension of calcium hydroxide particles in water. These particles give it the milky aspect. It is commonly produced by reacting quicklime (calcium oxide
) with an excess of water - usually 4 to 8 times the amount of water to the amount of quicklime. Reacting water with quicklime is sometimes referred to as "slaking" the lime. The calcium oxide will convert to the hydroxide according to the following reaction scheme:
This reaction is strongly exothermic
and will generate enough heat to bring the suspension to a scalding temperature. At a ratio of 2 parts water to 1 part lime (by weight), the generated heat is sufficient to bring the suspension, i.e. the water in it, to boil.
Milk of lime is an alkaline with a pH of 12.3. It is commonly used in the chemical industry and as a neutralizing agent in municipal waste water treatment. While it has a multitude of other uses, it is best known in its (historical) use as a paint: lime wash or whitewash
.
with distilled water
, or deionized water. The mixture needs to be shaken to ensure the solution is saturated with calcium hydroxide. It is then left to settle and the clear "saturated" solution is siphon
ed off the sediment
.
to produce a precipitate of calcium carbonate
:
If excess CO2 is added, the following reaction takes place:
CaCO3 + H2O + CO2 --> Ca(HCO3)2 (colourless)
Limewater is also used in experiments involving aerobic or anaerobic respiration, to determine whether carbon dioxide was produced, by first boiling the lime water and then pouring the solute into the boiling lime water. When limewater reacts with CO2 it becomes milky, because of the calcium carbonate, or chalk, produced.
-style medicine shows promoting various patent medicine
s were in full swing, lime water was often used as a part of the act. The sales
person would have an audience member blow through a straw
into a glass of lime water. Since the exhaled gas is carbon dioxide, the water would turn cloudy; the huckster
then announced that this reaction proved that the audience member suffered from some ailment. If too much carbon dioxide comes into contact with the cloudy lime water, it will cause the calcium carbonate
precipitate to redissolve to form soluble calcium bicarbonate
.
CaCO3(s) + CO2(g) + H2O(l) → Ca(HCO3)2(aq)
The huckster had a patent medicine bottle filled with vinegar
or some similar acid
. He then would pour some of the acid into the glass of cloudy lime water. The acid reacted
with the calcium carbonate, and the water would instantly clear. This demonstrated the potent effect of the nostrum he was selling to eliminate the "disease" demonstrated by the audience member.
process used in the traditional making of corn tortilla
s, tamales, corn chips and various other maize
products.
Mixing lime water with konjac
flour and water, the result is Japanese konnyaku, one of the ingredients in sukiyaki
.
painting, limewater is used as the colour solvent to apply on fresh plaster.
and alkalinity
for reef aquariums. Corals of order Scleractinia
build their endoskeleton
s from aragonite
(a polymorph
of calcium carbonate
) and by doing so, usually form a reef
. Calcium
concentration in natural seawater is about 420 ppm. When used for this purpose, lime water is also referred to as Kalkwasser.
Lime water, or some variation of it, is also used in tanning and making parchment. The lime is used as a dehairing agent based on its alkaline solution.
Saturation (chemistry)
In chemistry, saturation has six different meanings, all based on reaching a maximum capacity...
calcium hydroxide
Calcium hydroxide
Calcium hydroxide, traditionally called slaked lime, is an inorganic compound with the chemical formula Ca2. It is a colourless crystal or white powder and is obtained when calcium oxide is mixed, or "slaked" with water. It has many names including hydrated lime, builders lime, slack lime, cal, or...
solution
Solution
In chemistry, a solution is a homogeneous mixture composed of only one phase. In such a mixture, a solute is dissolved in another substance, known as a solvent. The solvent does the dissolving.- Types of solutions :...
. It is sparsely soluble. Its chemical formula is Ca(OH)2. Since calcium hydroxide is only sparsely soluble, i.e. ca. 1.5 g per liter at 25 °C, there is no visible distinction to clear water(homogeneous). Attentive observers will notice a slightly earthy smell. It is clearly distinguishable by the alkaline taste of the calcium hydroxide. The term lime refers to the mineral
Lime (mineral)
Lime is a general term for calcium-containing inorganic materials, in which carbonates, oxides and hydroxides predominate. Strictly speaking, lime is calcium oxide or calcium hydroxide. It is also the name for a single mineral of the CaO composition, occurring very rarely...
, rather than the fruit
Lime (fruit)
Lime is a term referring to a number of different citrus fruits, both species and hybrids, which are typically round, green to yellow in color, 3–6 cm in diameter, and containing sour and acidic pulp. Limes are a good source of vitamin C. Limes are often used to accent the flavors of foods and...
. When exposed with carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
, lime water turns into a milky solution.
While limewater is a clear solution, milk of lime on the other hand is a suspension of calcium hydroxide particles in water. These particles give it the milky aspect. It is commonly produced by reacting quicklime (calcium oxide
Calcium oxide
Calcium oxide , commonly known as quicklime or burnt lime, is a widely used chemical compound. It is a white, caustic, alkaline crystalline solid at room temperature....
) with an excess of water - usually 4 to 8 times the amount of water to the amount of quicklime. Reacting water with quicklime is sometimes referred to as "slaking" the lime. The calcium oxide will convert to the hydroxide according to the following reaction scheme:
- CaO + H2O → Ca(OH)2
This reaction is strongly exothermic
Exothermic
In thermodynamics, the term exothermic describes a process or reaction that releases energy from the system, usually in the form of heat, but also in the form of light , electricity , or sound...
and will generate enough heat to bring the suspension to a scalding temperature. At a ratio of 2 parts water to 1 part lime (by weight), the generated heat is sufficient to bring the suspension, i.e. the water in it, to boil.
Milk of lime is an alkaline with a pH of 12.3. It is commonly used in the chemical industry and as a neutralizing agent in municipal waste water treatment. While it has a multitude of other uses, it is best known in its (historical) use as a paint: lime wash or whitewash
Whitewash
Whitewash, or calcimine, kalsomine, calsomine, or lime paint is a very low-cost type of paint made from slaked lime and chalk . Various other additives are also used...
.
Making limewater
Limewater can be made by mixing excess calcium hydroxideCalcium hydroxide
Calcium hydroxide, traditionally called slaked lime, is an inorganic compound with the chemical formula Ca2. It is a colourless crystal or white powder and is obtained when calcium oxide is mixed, or "slaked" with water. It has many names including hydrated lime, builders lime, slack lime, cal, or...
with distilled water
Distilled water
Distilled water is water that has many of its impurities removed through distillation. Distillation involves boiling the water and then condensing the steam into a clean container.-History:...
, or deionized water. The mixture needs to be shaken to ensure the solution is saturated with calcium hydroxide. It is then left to settle and the clear "saturated" solution is siphon
Siphon
The word siphon is sometimes used to refer to a wide variety of devices that involve the flow of liquids through tubes. But in the English language today, the word siphon usually refers to a tube in an inverted U shape which causes a liquid to flow uphill, above the surface of the reservoir,...
ed off the sediment
Sediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
.
Chemistry
In chemistry, limewater can be used to detect the presence of carbon dioxide because limewater reacts with carbon dioxideCarbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
to produce a precipitate of calcium carbonate
Calcium carbonate
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...
:
- Ca(OH)2 (aq) + CO2 (g) → CaCO3 (s) + H2O (l)
If excess CO2 is added, the following reaction takes place:
CaCO3 + H2O + CO2 --> Ca(HCO3)2 (colourless)
Limewater is also used in experiments involving aerobic or anaerobic respiration, to determine whether carbon dioxide was produced, by first boiling the lime water and then pouring the solute into the boiling lime water. When limewater reacts with CO2 it becomes milky, because of the calcium carbonate, or chalk, produced.
Medicine
When the old vaudevilleVaudeville
Vaudeville was a theatrical genre of variety entertainment in the United States and Canada from the early 1880s until the early 1930s. Each performance was made up of a series of separate, unrelated acts grouped together on a common bill...
-style medicine shows promoting various patent medicine
Patent medicine
Patent medicine refers to medical compounds of questionable effectiveness sold under a variety of names and labels. The term "patent medicine" is somewhat of a misnomer because, in most cases, although many of the products were trademarked, they were never patented...
s were in full swing, lime water was often used as a part of the act. The sales
Sales
A sale is the act of selling a product or service in return for money or other compensation. It is an act of completion of a commercial activity....
person would have an audience member blow through a straw
Drinking straw
A drinking straw is a short tube intended for transferring a beverage from its container to the mouth of the drinker by use of suction. A thin tube of plastic or other material, straight or with an accordion-like living hinge, it is employed by being held with one end in the mouth and another end...
into a glass of lime water. Since the exhaled gas is carbon dioxide, the water would turn cloudy; the huckster
Huckster
A huckster is a seller of small articles, who tricks others into buying cheap imitation products and then bargains them as if they were the real thing...
then announced that this reaction proved that the audience member suffered from some ailment. If too much carbon dioxide comes into contact with the cloudy lime water, it will cause the calcium carbonate
Calcium carbonate
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...
precipitate to redissolve to form soluble calcium bicarbonate
Calcium bicarbonate
Calcium bicarbonate , also called calcium hydrogencarbonate, does not refer to a known solid compound; it exists only in aqueous solution containing the calcium , bicarbonate , and carbonate ions, together with dissolved carbon dioxide...
.
CaCO3(s) + CO2(g) + H2O(l) → Ca(HCO3)2(aq)
The huckster had a patent medicine bottle filled with vinegar
Vinegar
Vinegar is a liquid substance consisting mainly of acetic acid and water, the acetic acid being produced through the fermentation of ethanol by acetic acid bacteria. Commercial vinegar is produced either by fast or slow fermentation processes. Slow methods generally are used with traditional...
or some similar acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...
. He then would pour some of the acid into the glass of cloudy lime water. The acid reacted
Chemical reaction
A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...
with the calcium carbonate, and the water would instantly clear. This demonstrated the potent effect of the nostrum he was selling to eliminate the "disease" demonstrated by the audience member.
Culinary
Limewater can be used in the nixtamalizationNixtamalization
Nixtamalization typically refers to a process for the preparation of maize , or other grain, in which the grain is soaked and cooked in an alkaline solution, usually limewater, and hulled. The term can also refer to the removal via an alkali process of the pericarp from other grains such as sorghum...
process used in the traditional making of corn tortilla
Corn tortilla
In Mexico and Central America, a tortilla is a type of thin, unleavened flat bread, made from finely ground maize...
s, tamales, corn chips and various other maize
Maize
Maize known in many English-speaking countries as corn or mielie/mealie, is a grain domesticated by indigenous peoples in Mesoamerica in prehistoric times. The leafy stalk produces ears which contain seeds called kernels. Though technically a grain, maize kernels are used in cooking as a vegetable...
products.
Mixing lime water with konjac
Konjac
Konjac , also known as konjak, konjaku, konnyaku potato, devil's tongue, voodoo lily, snake palm, or elephant yam , is a plant of the genus Amorphophallus...
flour and water, the result is Japanese konnyaku, one of the ingredients in sukiyaki
Sukiyaki
Sukiyaki is a Japanese dish in the nabemono style.It consists of meat which is slowly cooked or simmered at the table, alongside vegetables and other ingredients, in a shallow iron pot in a mixture of soy sauce, sugar, and mirin...
.
Arts
In buon frescoFresco
Fresco is any of several related mural painting types, executed on plaster on walls or ceilings. The word fresco comes from the Greek word affresca which derives from the Latin word for "fresh". Frescoes first developed in the ancient world and continued to be popular through the Renaissance...
painting, limewater is used as the colour solvent to apply on fresh plaster.
Other uses
Limewater is widely used by marine aquarists and is a primary supplement of calciumCalcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
and alkalinity
Alkalinity
Alkalinity or AT measures the ability of a solution to neutralize acids to the equivalence point of carbonate or bicarbonate. The alkalinity is equal to the stoichiometric sum of the bases in solution...
for reef aquariums. Corals of order Scleractinia
Scleractinia
Scleractinia, also called stony corals, are exclusively marine animals; they are very similar to sea anemones but generate a hard skeleton. They first appeared in the Middle Triassic and replaced tabulate and rugose corals that went extinct at the end of the Permian...
build their endoskeleton
Endoskeleton
An endoskeleton is an internal support structure of an animal, composed of mineralized tissue. Endoskeleton develops within the skin or in the deeper body tissues. The vertebrate is basically an endoskeleton made up of two types of tissues . During early embryonic development the endoskeleton is...
s from aragonite
Aragonite
Aragonite is a carbonate mineral, one of the two common, naturally occurring, crystal forms of calcium carbonate, CaCO3...
(a polymorph
Polymorphism (materials science)
Polymorphism in materials science is the ability of a solid material to exist in more than one form or crystal structure. Polymorphism can potentially be found in any crystalline material including polymers, minerals, and metals, and is related to allotropy, which refers to chemical elements...
of calcium carbonate
Calcium carbonate
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...
) and by doing so, usually form a reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
. Calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
concentration in natural seawater is about 420 ppm. When used for this purpose, lime water is also referred to as Kalkwasser.
Lime water, or some variation of it, is also used in tanning and making parchment. The lime is used as a dehairing agent based on its alkaline solution.