sul·phu·ric acid /ˌsʌlˈfjʊrɪk-/



 Sul·phur n.
 1. Chem. A nonmetallic element occurring naturally in large quantities, either combined as in the sulphides (as pyrites) and sulphates (as gypsum), or native in volcanic regions, in vast beds mixed with gypsum and various earthy materials, from which it is melted out. Symbol S. Atomic weight 32. The specific gravity of ordinary octohedral sulphur is 2.05; of prismatic sulphur, 1.96.
 Note: ☞ It is purified by distillation, and is obtained as a lemon-yellow powder (by sublimation), called flour, or flowers, of sulphur, or in cast sticks called roll sulphur, or brimstone. It burns with a blue flame and a peculiar suffocating odor. It is an ingredient of gunpowder, is used on friction matches, and in medicine (as a laxative and insecticide), but its chief use is in the manufacture of sulphuric acid. Sulphur can be obtained in two crystalline modifications, in orthorhombic octahedra, or in monoclinic prisms, the former of which is the more stable at ordinary temperatures. Sulphur is the type, in its chemical relations, of a group of elements, including selenium and tellurium, called collectively the sulphur group, or family. In many respects sulphur resembles oxygen.
 2. Zool. Any one of numerous species of yellow or orange butterflies of the subfamily Pierinae; as, the clouded sulphur (Eurymus philodice syn. Colias philodice), which is the common yellow butterfly of the Eastern United States.
 Amorphous sulphur Chem., an elastic variety of sulphur of a resinous appearance, obtained by pouring melted sulphur into water. On standing, it passes back into a brittle crystalline modification.
 Liver of sulphur. Old Chem. See Hepar.
 Sulphur acid. Chem. See Sulphacid.
 Sulphur alcohol. Chem. See Mercaptan.
 Sulphur auratum [L.] Old Chem., a golden yellow powder, consisting of antimonic sulphide, Sb2S5, -- formerly a famous nostrum.
 Sulphur base Chem., an alkaline sulphide capable of acting as a base in the formation of sulphur salts according to the old dual theory of salts. [Archaic]
 Sulphur dioxide Chem., a colorless gas, SO2, of a pungent, suffocating odor, produced by the burning of sulphur. It is employed chiefly in the production of sulphuric acid, and as a reagent in bleaching; -- called also sulphurous anhydride, and formerly sulphurous acid.
 Sulphur ether Chem., a sulphide of hydrocarbon radicals, formed like the ordinary ethers, which are oxides, but with sulphur in the place of oxygen.
 Sulphur salt Chem., a salt of a sulphacid; a sulphosalt.
 Sulphur showers, showers of yellow pollen, resembling sulphur in appearance, often carried from pine forests by the wind to a great distance.
 Sulphur trioxide Chem., a white crystalline solid, SO3, obtained by oxidation of sulphur dioxide. It dissolves in water with a hissing noise and the production of heat, forming sulphuric acid, and is employed as a dehydrating agent. Called also sulphuric anhydride, and formerly sulphuric acid.
 Sulphur whale. Zool. See Sulphur-bottom.
 Vegetable sulphur Bot., lycopodium powder. See under Lycopodium.

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 Sul·phu·ric a.
 1. Of or pertaining to sulphur; as, a sulphuric smell.
 2. Chem. Derived from, or containing, sulphur; specifically, designating those compounds in which the element has a higher valence as contrasted with the sulphurous compounds; as, sulphuric acid.
 Sulphuric acid. (a) Sulphur trioxide (see under Sulphur); -- formerly so called on the dualistic theory of salts. [Obs.] (b) A heavy, corrosive, oily liquid, H2SO4, colorless when pure, but usually yellowish or brownish, produced by the combined action of sulphur dioxide, oxygen (from the air), steam, and nitric fumes. It attacks and dissolves many metals and other intractable substances, sets free most acids from their salts, and is used in the manufacture of hydrochloric and nitric acids, of soda, of bleaching powders, etc. It is also powerful dehydrating agent, having a strong affinity for water, and eating and corroding paper, wood, clothing, etc.   It is thus used in the manufacture of ether, of imitation parchment, and of nitroglycerin. It is also used in etching iron, in removing iron scale from forgings, in petroleum refining, etc., and in general its manufacture is the most important and fundamental of all the chemical industries. Formerly called vitriolic acid, and now popularly vitriol, and oil of vitriol.
 Fuming sulphuric acid, or Nordhausen sulphuric acid. See Disulphuric acid, under Disulphuric.
 Sulphuric anhydride, sulphur trioxide. See under Sulphur.
 Sulphuric ether, common anaesthetic ether; -- so called because made by the catalytic action of sulphuric acid on alcohol. See Ether, 3 (a).

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 Tow·er n.
 1. Arch. (a) A mass of building standing alone and insulated, usually higher than its diameter, but when of great size not always of that proportion. (b) A projection from a line of wall, as a fortification, for purposes of defense, as a flanker, either or the same height as the curtain wall or higher. (c) A structure appended to a larger edifice for a special purpose, as for a belfry, and then usually high in proportion to its width and to the height of the rest of the edifice; as, a church tower.
 2. A citadel; a fortress; hence, a defense.
    Thou hast been a shelter for me, and a strong tower from the enemy.   --Ps. lxi. 3.
 3. A headdress of a high or towerlike form, fashionable about the end of the seventeenth century and until 1715; also, any high headdress.
 Lay trains of amorous intrigues
 In towers, and curls, and periwigs.   --Hudibras.
 4. High flight; elevation. [Obs.]
 Gay Lussac's tower Chem., a large tower or chamber used in the sulphuric acid process, to absorb (by means of concentrated acid) the spent nitrous fumes that they may be returned to the Glover's tower to be reemployed. See Sulphuric acid, under Sulphuric, and Glover's tower, below.
 Glover's tower Chem., a large tower or chamber used in the manufacture of sulphuric acid, to condense the crude acid and to deliver concentrated acid charged with nitrous fumes. These fumes, as a catalytic, effect the conversion of sulphurous to sulphuric acid. See Sulphuric acid, under Sulphuric, and Gay Lussac's tower, above.
 Round tower. See under Round, a.
 Shot tower. See under Shot.
 Tower bastion Fort., a bastion of masonry, often with chambers beneath, built at an angle of the interior polygon of some works.
 Tower mustard Bot., the cruciferous plant Arabis perfoliata.
 Tower of London, a collection of buildings in the eastern part of London, formerly containing a state prison, and now used as an arsenal and repository of various objects of public interest.


 Vit·ri·ol n.  Chem. (a) A sulphate of any one of certain metals, as copper, iron, zinc, cobalt. So called on account of the glassy appearance or luster.  (b) Sulphuric acid; -- called also oil of vitriol. So called because first made by the distillation of green vitriol.  See Sulphuric acid, under Sulphuric.  [Colloq.]
 Blue vitriol. See under Blue.
 Green vitriol, ferrous sulphate; copperas.  See under Green.
 Oil of vitriol, sulphuric or vitriolic acid; -- popularly so called because it has the consistency of oil.
 Red vitriol, a native sulphate of cobalt.
 Vitriol of Mars, ferric sulphate, a white crystalline substance which dissolves in water, forming a red solution.
 White vitriol, zinc sulphate, a white crystalline substance used in medicine and in dyeing. It is usually obtained by dissolving zinc in sulphuric acid, or by roasting and oxidizing certain zinc ores. Formerly called also vitriol of zinc.


 sulphuric acid
      n : (H2SO4) a highly corrosive acid made from sulfur dioxide;
          widely used in the chemical industry [syn: vitriol, {oil
          of vitriol, sulfuric acid]