alkali


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alkali

(ăl`kəlī) [Arab., al-gili=ashes of saltwort], hydroxidehydroxide
, chemical compound that contains the hydroxyl (−OH) radical. The term refers especially to inorganic compounds. Organic compounds that have the hydroxyl radical as a functional group are called alcohols; the hydroxyl radical is also present in the carboxyl group
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 of an alkali metalalkali metals,
metals found in Group 1 of the periodic table. Compared to other metals they are soft and have low melting points and densities. Alkali metals are powerful reducing agents and form univalent compounds.
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. Alkalies are readily soluble in water and form strongly basic solutions with a characteristic acrid taste. They neutralize acids, forming salts and water. Strong alkalies (e.g., those of sodium or potassium) are sometimes called caustic alkalies. The term alkali originally applied to salts obtained from plant ashes and is sometimes applied to a carbonate of sodium or potassium or to the hydroxide of an alkaline-earth metalalkaline-earth metals,
metals constituting Group 2 of the periodic table. Generally, they are softer than most other metals, react readily with water (especially when heated), and are powerful reducing agents, but they are exceeded in each of these properties by the
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.

Alkali

 

a base in aqueous solution. Aqueous alkaline solutions have high concentrations of OH (hydroxyl) ions. Alkalies include the hydroxides of the alkali metals, the alkaline-earth metals, and ammonium.

Most alkalies are highly hygroscopic white solid compounds. Their dissolution in water is accompanied by the liberation of large amounts of heat. Alkaline solutions change the color of acid-base indicators. The strongest, that is, caustic, alkalies are the hydroxides of the alkali metals, such as NaOH and KOH, while the weakest alkalies are ammonium hydroxide and the hydroxides of the alkaline-earth metals, such as Ca(OH)2 and Ba(OH)2. Also sometimes considered as alkalies are the salts of strong bases and weak acids (seeACIDS AND BASES), whose aqueous solutions exhibit alkaline reactions, for example, the hydro-sulfides NaSH and KSH, the carbonates Na2CO3 and K2CO3, the hydrocarbonate NaHCO3 and the borax Na2B4O7. Alkalies are commonly used in laboratory work and in industry (seeSODIUM HYDROXIDE; POTASSIUM HYDROXIDE; and CALCIUM HYDROXIDE).

alkali

[′al·kə‚lī]
(chemistry)
Any compound having highly basic qualities.
(petrology)

alkali

Any of the various chemically active bases such as the soluble salts of metals, e.g., the water-soluble salts of sodium and potassium which occur in constituents of concrete and mortar that may result in deleterious expansion.

alkali

1. Chem a soluble base or a solution of a base
2. a soluble mineral salt that occurs in arid soils and some natural waters
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Alkali, water and fluidity effect on mechanical properties of alkali-activated materials on base fly ash.
Darren James, managing director of Red Square Residential, said: "When the Alkali went up for lease, it immediately caught our interest.
Also micro-crystalline or imperfectly crystallised quartz (stressed quartz) may be the reason for alkali reactivity in similar slow alkali-reactive aggregates [8].
When alkali bees find a suitable stretch of barren land, each female excavates a shaft ending in a cluster of nursery chambers about the size of small table grapes.
Tronox Alkali is the world's largest producer of natural soda ash, which is used by customers in the glass, detergent, and chemical manufacturing industries.
Since, caustic soda serves as a major raw material in the refining process of alumina, growth in the alumina industry is expected to propel the demand for caustic soda in the coming years, thus benefiting the market for chlor alkali chemicals market in the long run,” said Mr.
Interested parties involved in the research or production of alkali activated fly ash or natural pozzotan products are invited to join in the ongoing development of ASTM WK42602.
Hypercalcemia without hypercalciuria or hypophosphatemia, calcinosis and renal insufficiency: a syndrome following prolonged intake of milk and alkali.
Encapsulating alkali metals into silica gel enables scientists who have traditionally shied away from these metals to now safely and routinely perform reductions," said Sigma-Aldrich director of business development for chemistry Chris Hewitt.
Oceanic island rocks form two major families based on mineralogy and petrography: those that form from tholeiitic basalts and those from alkali basalts.
The general pattern of the alkali impregnation of eucalyptus wood is similar to that of poplar wood.
PMC first entered the alkali blue market in 1985, when the company acquired Sherwin-Williams' operations.