water plantain, (genus Alisma), any freshwater perennial herb of the genus Alisma (family Alismataceae), commonly found in lakes, ponds, and ditches. The 9 to 11 species of water plantains are primarily distributed throughout the Northern Hemisphere, 3 being native to North America. Water plantains

water plantain: subcordatum and A. orientale (sometimes listed as a subspecies of A. plantago-aquatica), have been used as food and in traditional Native American and Chinese medicine.

water plantain: …variety of the European species A. plantago-aquatica, is common throughout North America. The plant grows to about 1 metre (39 inches) in height and has ovate, slightly pointed leaves. The flowers grow in whorls along a many-branched stalk. Some species, including A. subcordatum and A. orientale (sometimes listed as a…

water plantain: Some species, including A. subcordatum and A. orientale (sometimes listed as a subspecies of A. plantago-aquatica), have been used as food and in traditional Native American and Chinese medicine.

water plantain: Alisma triviale, regarded by some authorities as a New World variety of the European species A. plantago-aquatica, is common throughout North America. The plant grows to about 1 metre (39 inches) in height and has ovate, slightly pointed leaves. The flowers grow in whorls along…

Alismatales, arrowhead and pondweed order of nearly 4,800 species and 166 genera of flowering plants, belonging to the monocotyledon (monocot) group, whose species have a single seed leaf. The order contains 14 families that are broadly distributed throughout temperate and tropical regions with

Alismataceae, the water plantain family of 113 species of freshwater flowering plants belonging to the order Alismatales and including 17 genera, the most common of which are Alisma (water plantain), Echinodorus (burhead), and Sagittaria (arrowhead). Most members of the family are native to the

Alismatales, arrowhead and pondweed order of nearly 4,800 species and 166 genera of flowering plants, belonging to the monocotyledon (monocot) group, whose species have a single seed leaf. The order contains 14 families that are broadly distributed throughout temperate and tropical regions with

Alisol, one of the 30 soil groups in the classification system of the Food and Agriculture Organization (FAO). Alisols are highly acidic, poorly drained soils prone to aluminum toxicity and water erosion. Liming and fertilization are essential to their agricultural use—primarily for growing oil

Susan Glaspell: …married for a time), and Alison’s House (1930), a play that was awarded the Pulitzer Prize. Her later novels included The Fugitive’s Return (1929) and The Morning Is Near Us (1939).

aesthetics: Major concerns of 18th-century aesthetics: Meanwhile, Lord Kames and Archibald Alison had each provided full accounts of the role of association in the formation and justification of critical judgment. Alison, in particular, recognized the inadequacies of the traditional Empiricist approach to imaginative association and provided a theory as to how the feelings aroused by…

James Cameron: Avatar: …screenplay for the sci-fi thriller Alita: Battle Angel (2019), an adaptation of a manga series. In 2022 Cameron released Avatar: The Way of Water, which he directed and cowrote; it became the third-biggest box office hit of all time. The third installment of the franchise, titled Avatar: Fire and Ash,…

Alitalia–Linee Aeree Italiane, Italian international airline founded in 1946 and, by the early 21st century, serving more than 80 cities in Europe, Africa, Asia, North and South America, and Australia. Headquarters are in Rome. The pope usually flies on a chartered Alitalia jet nicknamed “Shepherd

Samuel A. Alito, Jr. is an associate justice of the Supreme Court of the United States from 2006. Alito is known for his judicial conservatism and his many famous Supreme Court opinions, including McDonald v. City of Chicago (2010), which held that state and local laws restricting the right to bear

Samuel A. Alito, Jr. is an associate justice of the Supreme Court of the United States from 2006. Alito is known for his judicial conservatism and his many famous Supreme Court opinions, including McDonald v. City of Chicago (2010), which held that state and local laws restricting the right to bear

Alytus, city, southern Lithuania. It lies along the Neman (Lithuanian: Nemunas) River, 37 miles (60 km) south of Kaunas. The city dates from the 14th century. In the 20th century it developed as an industrial centre, with factories producing refrigerators, chemical products, linen, and clothing.

Paleo-Siberian languages: Yeniseian, Luorawetlan, and Nivkh: …west coast of Kamchatka, (4) Aliutor, perhaps a Koryak dialect, with about 2,000 speakers, and (5) Kerek, with about 10 speakers.

Ethan Hawke: Early films: Dead Poets Society and Reality Bites: …adaptation of Jack London’s novel; Alive (1993), a drama based on the true story of an Uruguayan rugby team’s fight for survival after its plane crashes in the Andes Mountains; and Reality Bites (1994), which centers on a group of twentysomethings trying to figure out what they want to do…

Lisel Mueller: …in 1997 for her volume Alive Together: New and Selected Poems.

bivalve: The shell: …externally (parivincular) or internally (alivincular) but comprises outer lamellar, and inner fibrous, layers secreted by the mantle crest. The ligament type is generally characteristic of each bivalve group. The hinge plate with ligament also possesses interlocking teeth to enforce valve alignment and locking, when closed, to prevent shear. Many…

Peter I: …II Augustus of France to Alix, heiress to Brittany, Peter did homage for the province in 1213 and assumed the title of duke, though he was considered merely a count by the French. He energetically asserted his authority over the Breton lands, annexing new fiefs to the ducal domain, granting…

Alexandra was the consort of the Russian emperor Nicholas II. Her misrule while the emperor was commanding the Russian forces during World War I precipitated the collapse of the imperial government in March 1917. A granddaughter of Queen Victoria and daughter of Louis IV, grand duke of

aliyah, a Hebrew term that translates as “going up” or “ascent” and has two predominant related meanings in Judaism. In the context of worship in a synagogue, aliyah is the honor accorded to a congregant of being called up to the bimah (central platform) to recite a blessing and, depending on the

Azerbaijan: First Nagorno-Karabakh conflict, dissolution of the Soviet Union, and presidency of Heydar Aliyev: …overthrown in June 1993 by Heydar Aliyev, a former KGB official and leader of the Azerbaijani Communist Party who had adopted the rhetoric of Azerbaijani nationalism.

Ilham Aliyev is the longtime president of Azerbaijan (2003– ) who has leveraged the country’s oil wealth to enrich his autocratic rule and build up a military capacity that in the 2020s allowed Azerbaijan to take control of Nagorno-Karabakh, a region of southwestern Azerbaijan that had asserted its

aliyah, a Hebrew term that translates as “going up” or “ascent” and has two predominant related meanings in Judaism. In the context of worship in a synagogue, aliyah is the honor accorded to a congregant of being called up to the bimah (central platform) to recite a blessing and, depending on the

aliyah, a Hebrew term that translates as “going up” or “ascent” and has two predominant related meanings in Judaism. In the context of worship in a synagogue, aliyah is the honor accorded to a congregant of being called up to the bimah (central platform) to recite a blessing and, depending on the

Alibaba: 2007–2016: Further expansion and two IPOs: … arm of Alibaba, known as Alibaba Cloud, launched in 2009. Also known as Aliyun, Alibaba Cloud has grown rapidly to provide cloud services to at least 30 regions globally. AliExpress, an international retail platform that connects Chinese manufacturers and distributors with individual consumers, got its start in 2010—a development that…

aliyah, a Hebrew term that translates as “going up” or “ascent” and has two predominant related meanings in Judaism. In the context of worship in a synagogue, aliyah is the honor accorded to a congregant of being called up to the bimah (central platform) to recite a blessing and, depending on the

aliyah, a Hebrew term that translates as “going up” or “ascent” and has two predominant related meanings in Judaism. In the context of worship in a synagogue, aliyah is the honor accorded to a congregant of being called up to the bimah (central platform) to recite a blessing and, depending on the

alizarin, a red dye originally obtained from the root of the common madder plant, Rubia tinctorum, in which it occurs combined with the sugars xylose and glucose. The cultivation of madder and the use of its ground root for dyeing by the complicated Turkey red process were known in ancient India,

alizarin, a red dye originally obtained from the root of the common madder plant, Rubia tinctorum, in which it occurs combined with the sugars xylose and glucose. The cultivation of madder and the use of its ground root for dyeing by the complicated Turkey red process were known in ancient India,

Mali: Climate: …and is influenced by the alize and harmattan winds. The alize blows from the northeast from November to January and causes a relatively cool spell, with temperatures averaging 77 °F (25 °C). From March to June the harmattan, a dry, hot wind that blows from the east out of the…

Mudejar: …giving rise to their characteristic aljamiado literature.

Alexander Alekhine was a world champion chess player from 1927 to 1935 and from 1937 until his death, noted for using a great variety of attacks. (Read Garry Kasparov’s Britannica essay on chess & Deep Blue.) Alekhine was a precocious chess player, becoming a master at age 16 and a grandmaster at

Batalha: In the Battle of Aljubarrota, fought on a plain 9 miles (14 km) southwest of the town, John I of Portugal defeated John I of Castile in 1385 and secured the independence of his kingdom. The abbey was probably founded in 1388 to commemorate the victory. The…

neuroblastoma: Treatment and development of targeted therapies: … in a gene known as ALK (anaplastic lymphoma kinase) are present in tumours from approximately 8–10 percent of patients. Agents known as crizotinib and ceritinib, which target the abnormal gene products of ALK, have been approved by the U.S. Food and Drug Administration (FDA) for non-small-cell lung cancer patients with…

alka, in Baltic religion, an open-air religious site, a natural sanctuary—forest, hill, river—that was sacred and inviolate. Trees could not be cut in such forests, sacred fields could not be plowed, and fishing was not allowed in the holy waters. The rituals of various religious cults, involving

hydrocarbon: Nomenclature of alkenes and alkynes: …double bonds are classified as dienes, those with three as trienes, and so forth. Dienes are named by replacing the -ane suffix of the corresponding alkane by -adiene and identifying the positions of the double bonds by numerical locants. Dienes are classified as cumulated, conjugated, or isolated according to whether…

Alcaeus was a Greek lyric poet whose work was highly esteemed in the ancient world. He lived at the same time and in the same city as the poet Sappho. A collection of Alcaeus’s surviving poems in 10 books (now lost) was made by scholars in Alexandria, Egypt, in the 2nd century bce, and he was a

Judah ben Solomon Hai Alkalai was a Sephardic rabbi and an early advocate of Jewish colonization of Palestine. Alkalai was taken to Jerusalem at an early age, and there he was reared and educated for the rabbinate. At 25 he went to Semlin, in Croatia, as a rabbi and found himself teaching Hebrew to

alkalosis: Metabolic alkalosis results from either acid loss (which may be caused by severe vomiting or by the use of potent diuretics [substances that promote production of urine]) or bicarbonate gain (which may be caused by excessive intake of bicarbonate or by the depletion of body…

alkali, any of the soluble hydroxides of the alkali metals—i.e., lithium, sodium, potassium, rubidium, and cesium. Alkalies are strong bases that turn litmus paper from red to blue; they react with acids to yield neutral salts; and they are caustic and in concentrated form are corrosive to organic

rocket and missile system: Air-to-air: …in the 1960s with the AA-1 Alkali, a relatively primitive semiactive radar missile, the AA-2 Atoll, an infrared missile closely modeled after the Sidewinder, and the AA-3 Anab, a long-range, semiactive radar-homing missile carried by air-defense fighters. The AA-5 Ash was a large, medium-range radar-guided missile, while the AA-6 Acrid…

Halton: …refuse dumps, but the first Alkali Act of 1862 was the beginning of the slow introduction of stricter operating conditions. Widnes town centre developed in the second half of the 19th century around Victoria Square.

basalt: Normal alkali basalt contains olivine and, commonly, a diopsidic or titaniferous augite. Alkali basalts predominate among the lavas of the ocean basins and are common among the mafic lavas of the forelands and backlands of the mountain belts. In the Brito-Icelandic province the Paleogene and Neogene…

pollination: Bees: Alkali bees (Nomia) and leaf-cutter bees (Megachile) are both efficient pollinators of alfalfa; unlike honeybees, they are not afraid to trigger the explosive mechanism that liberates a cloud of pollen in alfalfa flowers. Certain Ecuadorian orchids (Oncidium) are pollinated by male bees of the genus…

alkali feldspar, any of several common silicate minerals that often occur as variously coloured, glassy crystals. They are used in the manufacture of glass and ceramics; transparent, highly coloured, or iridescent varieties are sometimes used as gemstones. The alkali feldspars are primarily

alkali flat, a playa, or dried-out desert lake, especially one containing high concentrations of precipitated dry, glistening salts. The term is generally limited to flats in the western United States, the most famous being the Bonneville Salt Flats (q.v.) west of Salt Lake City, where automobile

White Sands National Park: The extensive Alkali Flat area, to the north of the lake, is similarly created by underground water drawn to the surface. There is little plant life; the animals, mainly mice and lizards, are light-hued, blending with the sand. To the west is San Andres National Wildlife Refuge.…

crystal: Ionic bonds: The alkali halide crystals are binaries of the AH type, where A is an alkali ion (lithium [Li], sodium, potassium, rubidium, or cesium) and H is a halide ion (fluorine, chlorine, bromine, or iodine). The crystals have ionic bonding, and each ion has six or eight…

lake: Chemical precipitates: …containing sodium carbonate are called alkali lakes. Soda Lake, California, is estimated to contain nearly one million tons of anhydrous sulfate. Magnesium salts of these types are also quite common and can be found in the same sediments as the sodium salts. Other salts of importance occurring in lake sediments…

alkali flat, a playa, or dried-out desert lake, especially one containing high concentrations of precipitated dry, glistening salts. The term is generally limited to flats in the western United States, the most famous being the Bonneville Salt Flats (q.v.) west of Salt Lake City, where automobile

alkali metal, any of the six chemical elements that make up Group 1 (Ia) of the periodic table—namely, lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). The alkali metals are so called because reaction with water forms alkalies (i.e., strong bases capable of

fat and oil processing: Alkali refining: Many of these can be removed by treating fats at 40 to 85 °C (104 to 185 °F) with an aqueous solution of caustic soda (sodium hydroxide) or soda ash (sodium carbonate). The refining may be done in a tank (in which case…

desert: Flora: …and generally less well-known family Frankeniaceae, which is typical of salty habitats and reaches its greatest diversity in deserts from North Africa to Central Asia and in western South America.

amorphous solid: Properties of oxide glasses: …a partial replacement for soda, lead-alkali-silicate glasses result that have lower softening points than lime glasses. The refractive indices, dispersive powers, and electrical resistance of these glasses are generally much greater than those of soda-lime-silica glasses.

alkaline rock, any of various rocks in which the chemical content of the alkalies (potassium oxide and sodium oxide) is great enough for alkaline minerals to form. Such minerals may be unusually sodium rich, with a relatively high ratio of alkalies to silica (SiO2), as in the feldspathoids. Other

battery: Zinc–manganese dioxide systems: …found in batteries with an alkaline electrolyte, which permits a completely different type of construction. The alkaline battery became commercially available during the 1950s and is now the most popular household battery. A cathode of a very pure manganese dioxide–graphite mixture and an anode of a powdered zinc alloy are…

papermaking: Bleaching and washing: In the following stage an alkaline extraction with dilute caustic soda dissolves chlorinated compounds, which are then washed out.

fuel cell: Alkaline fuel cells: These are devices that, by definition, have an aqueous solution of sodium hydroxide or potassium hydroxide as the electrolyte. The fuel is almost always hydrogen gas, with oxygen (or oxygen in air) as the oxidizer. However, zinc or aluminum could be used…

sperm oil: Saponification yielded fatty acids for soap manufacture and fatty alcohols for cosmetics and detergents.

alkaline phosphatase, enzyme that is normally present in high concentrations in growing bone and in bile. It is essential for the deposition of minerals in the bones and teeth. Alkaline phosphatase deficiency is a hereditary trait called hypophosphatasia, which results in bone deformities. In

nepheline: …is the characteristic mineral of alkaline plutonic rocks, particularly nepheline syenites and nepheline gneisses. It occurs in beautiful crystal form with mica, garnet, and sanidine feldspar on Monte Somma, Vesuvius, Italy. For detailed physical properties, see feldspathoid (table).

alkaline rock, any of various rocks in which the chemical content of the alkalies (potassium oxide and sodium oxide) is great enough for alkaline minerals to form. Such minerals may be unusually sodium rich, with a relatively high ratio of alkalies to silica (SiO2), as in the feldspathoids. Other

battery: Alkaline storage batteries: In secondary batteries of this type, electric energy is derived from the chemical action in an alkaline solution. Such batteries feature a variety of electrode materials; some of the more notable ones are briefly discussed in this section.

alkaline-earth metal, any of the six chemical elements that comprise Group 2 (IIa) of the periodic table. The elements are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). Prior to the 19th century, substances that were nonmetallic, insoluble in water, and

alkalosis: …acidity, or high level of alkalinity, in the body fluids, including the blood. Alkalosis may be either metabolic or respiratory in origin. Metabolic alkalosis results from either acid loss (which may be caused by severe vomiting or by the use of potent diuretics [substances that promote production of urine]) or…

extremophile: …pH 1 and pH 5); alkaliphilic (optimal growth above pH 9); halophilic (optimal growth in environments with high concentrations of salt); thermophilic (optimal growth between 60 and 80 °C [140 and 176 °F]); hyperthermophilic (optimal growth above 80 °C [176 °F]); psychrophilic (optimal growth at 15 °C [60 °F] or…

extremophile: …pH 1 and pH 5); alkaliphilic (optimal growth above pH 9); halophilic (optimal growth in environments with high concentrations of salt); thermophilic (optimal growth between 60 and 80 °C [140 and 176 °F]); hyperthermophilic (optimal growth above 80 °C [176 °F]); psychrophilic (optimal growth at 15 °C [60 °F] or…

alkaloid, any of a class of naturally occurring organic nitrogen-containing bases. Alkaloids have diverse and important physiological effects on humans and other animals. Well-known alkaloids include morphine, strychnine, quinine, ephedrine, and nicotine. Alkaloids are found primarily in plants and

bacteria: pH: In contrast to acidophilic bacteria, alkalophilic bacteria are able to grow in alkaline concentrations as great as pH 10 to 11. Alkalophiles have been isolated from soils, and most are species of the gram-positive genus Bacillus.

alkalosis, abnormally low level of acidity, or high level of alkalinity, in the body fluids, including the blood. Alkalosis may be either metabolic or respiratory in origin. Metabolic alkalosis results from either acid loss (which may be caused by severe vomiting or by the use of potent diuretics

Valentin Alkan was a French pianist-composer, a notable keyboard virtuoso, and one of the most enigmatic figures in 19th-century music. Alkan was born to Jewish parents, and all of his siblings (five brothers and a sister) were musicians who assumed the surname Alkan. Valentin drew notice at age

Valentin Alkan was a French pianist-composer, a notable keyboard virtuoso, and one of the most enigmatic figures in 19th-century music. Alkan was born to Jewish parents, and all of his siblings (five brothers and a sister) were musicians who assumed the surname Alkan. Valentin drew notice at age

paraffin hydrocarbon, any of the saturated hydrocarbons having the general formula CnH2n+2, C being a carbon atom, H a hydrogen atom, and n an integer. The paraffins are major constituents of natural gas and petroleum. Paraffins containing fewer than 5 carbon atoms per molecule are usually gaseous

alkanet, any plant of the 50 or so mostly Mediterranean species of the genus Anchusa and the closely related Pentaglottis sempervirens, bearing blue, purple, or white flowers, similar to those of forget-me-nots, on hairy herbaceous stems. They belong to the family Boraginaceae. True alkanet (A.

alkanet: …closely related Alkanna tinctoria is dyer’s alkanet. Its roots yield a water-insoluble red dye used to colour fat, oil, perfume, wood, marble, and pharmaceutical products.

renal system: Volume and composition: …identified by the presence of homogentisic acid in the urine, is due to lack of the enzyme that catalyzes the oxidation of homogentisic acid; deposits of the acid in the tissues may cause chronic arthritis or spinal disease. Other such disorders are cystinuria, the presence of the amino acid cystine…

alkaptonuria, rare (one in 250,000 to 1,000,000 births) inherited disorder of protein metabolism, the primary distinguishing symptom of which is urine that turns black following exposure to air. It is characterized biochemically by an inability of the body to metabolize the amino acids tyrosine and

alka, in Baltic religion, an open-air religious site, a natural sanctuary—forest, hill, river—that was sacred and inviolate. Trees could not be cut in such forests, sacred fields could not be plowed, and fishing was not allowed in the holy waters. The rituals of various religious cults, involving

Xanana Gusmão: …the resignation of Prime Minister Mari Alkatiri, who was alleged to have ordered the intimidation and assassination of political opponents. The allegations resulted in mass protests, and Alkatiri stepped down in June.

Cáceres, city, capital of Cáceres provincia (province), in Extremadura comunidad autónoma (autonomous community), western Spain. It is built on a low east-west ridge south of the Tagus River and about 50 miles (80 km) northeast of Badajoz. Cáceres originated as the Roman town of Norba Caesarina,

Ebrahim Alkazi was the doyen of contemporary theatre in India and one of the country’s leading post-independence theatre directors. Alkazi’s father was a Bedouin trader from Saudi Arabia and his mother a Kuwaiti. The young Alkazi began his theatrical career in the English-language Theatre Group of

olefin, compound made up of hydrogen and carbon that contains one or more pairs of carbon atoms linked by a double bond. Olefins are examples of unsaturated hydrocarbons (compounds that contain only hydrogen and carbon and at least one double or triple bond). They are classified in either or both

organometallic compound: Simple alkyl ligands: …The reverse of this reaction, alkene insertion into the M―H bond, is illustrated by the hydroboration and hydrosilation reactions discussed above. Both the β-hydrogen elimination and addition of M―H across a C=C double bond are thought to proceed through a cyclic intermediate involving a three-centre, two-electron bond where a hydrogen…

Alcestis, drama by Euripides, performed in 438 bce. Though tragic in form, the play ends happily. It was performed in place of the satyr play that usually ended the series of three tragedies that were produced for festival competition. The story concerns the imminent death of King Admetus, who is

alka, in Baltic religion, an open-air religious site, a natural sanctuary—forest, hill, river—that was sacred and inviolate. Trees could not be cut in such forests, sacred fields could not be plowed, and fishing was not allowed in the holy waters. The rituals of various religious cults, involving

Alkmaar, gemeente (municipality), northwestern Netherlands. It lies along the North Holland Canal, 6 miles (10 km) east of the North Sea. The English missionaries Willibrord and Adalbert preached Christianity in the district in the 8th century. A fishing village in the 10th century, Alkmaar

Alkmaar: Under the Convention of Alkmaar (1799), a Russo-British army withdrew from the Netherlands after an unsuccessful campaign to overthrow the Batavian Republic.

Rabbe Enckell: …Orfeus och Eurydike (1938) and Alkman (1959). Enckell reflects upon this continuous preoccupation with the classical myths of Greece in his most remarkable collection of poetry, Andedräkt av koppar (1946; “Breath of Copper”). In 1960 he was made poet laureate of Swedish Finland.

alcohol: Acidity of alcohols: formation of alkoxides: Alcohols are weak acids. The most acidic simple alcohols (methanol and ethanol) are about as acidic as water, and most other alcohols are somewhat less acidic.

food preservation: Autoxidation: …that may break down into alkoxy (LO · ) and peroxy radicals plus water (H2O). The lipid, alkoxy, and peroxy radicals may combine with one another (or other radicals) to form stable, nonpropagating products (termination). These products result in the development of rancid off-flavours. In addition to promoting rancidity, the…

art conservation and restoration: Stone sculpture: …similar manner, the application of alkoxy silanes in recent decades offers the conservator a method by which amorphous silica can be introduced as a binder and strengthener for deteriorated sandstone. Some silanes will also impart water repellency to the stone. Synthetic polymer-based consolidants include acrylic polymers, epoxies, and polyesters. Although…

alkyd resin, a complex oil-modified polyester that serves as the film-forming agent in some paints and clear coatings. Developed in the 1920s, alkyd-based enamel paints were once one of the most important types of surface coating. Owing to their incorporation of volatile organic solvents and to

alkyd resin, a complex oil-modified polyester that serves as the film-forming agent in some paints and clear coatings. Developed in the 1920s, alkyd-based enamel paints were once one of the most important types of surface coating. Owing to their incorporation of volatile organic solvents and to

organohalogen compound: Nucleophilic substitution: Alkyl fluorides have the strongest carbon-halogen bond and react so slowly as to rarely undergo nucleophilic substitutions.

carbonium ion: Preparation and stability.: …of an alkyl, or hydrocarbon, group), of a carbon–carbon or carbon–hydrogen single bond. Since carbonium ions are positively charged species, they are most readily formed in relatively polar solvents (solvents consisting of molecules with unsymmetrical distribution of electrons), which help disperse their charges or the charges on the accompanying negative…

alcohol: Substitution to form alkyl halides: Alkyl halides are often synthesized from alcohols, in effect substituting a halogen atom for the hydroxyl group. Hydrochloric (HCl), hydrobromic (HBr), and hydroiodic (HI) acids are useful reagents for this substitution, giving their best yields with tertiary alcohols. Thionyl chloride (SOCl2), phosphorus tribromide…

organohalogen compound: Nucleophilic substitution: Alkyl iodides have the weakest carbon-halogen bond and react at the fastest rate. Alkyl fluorides have the strongest carbon-halogen bond and react so slowly as to rarely undergo nucleophilic substitutions.