- Key People:
- Joseph Priestley
- Joseph-Louis Gay-Lussac
- Related Topics:
- hydrochloric acid
- hydrogen halide
hydrogen chloride
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What is hydrogen chloride?
Hydrogen chloride (HCl) is a compound of hydrogen and chlorine, existing as a gas at room temperature and pressure. It can be synthesized by combining chlorine gas (Cl₂) and hydrogen gas (H₂) at temperatures exceeding 250 °C (482 °F).
When hydrogen chloride gas dissolves in water, it forms hydrochloric acid, a corrosive acid typically marketed in a 28–35 percent concentration. Hydrogen chloride is a colorless, pungent, poisonous gas that fumes in moist air. It is highly soluble in water, with water dissolving 477 times its volume of the gas at 20 °C (68 °F).
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What elements make up hydrogen chloride?
Hydrogen chloride (HCl) is a compound composed of the elements hydrogen (H) and chlorine (Cl). At room temperature and pressure, it exists as a gas. When hydrogen chloride gas is dissolved in water, it forms hydrochloric acid.
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What does hydrogen chloride look like as a gas?
As a gas, hydrogen chloride (HCl) is colorless and has a strong, pungent odor. It fumes in moist air because it is very soluble in water. When hydrogen chloride gas is dissolved in water, it forms hydrochloric acid.
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How does hydrogen chloride react with water?
Hydrogen chloride ((HCl)) is a compound of hydrogen and chlorine that exists as a gas at room temperature and pressure. When hydrogen chloride gas dissolves in water, it forms hydrochloric acid.
The reaction between hydrogen chloride and water can be represented by the equation:
[H_2O + HCl \rightleftharpoons H_3O^+ + Cl^-]
In this reaction, water acts as a base and accepts a proton ((H^+)) from hydrogen chloride, forming a hydronium ion ((H_3O^+)) and a chloride ion ((Cl^-)). This process is known as dissociation, and because it is extensive, hydrochloric acid is considered a strong acid.
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What is hydrochloric acid and how is it related to hydrogen chloride?
Hydrogen chloride (HCl) is a compound of hydrogen and chlorine that exists as a gas at room temperature and pressure. When this gas is dissolved in water, it forms hydrochloric acid, a corrosive and strong acid.
Hydrogen chloride can be synthesized by combining chlorine gas and hydrogen gas at temperatures above 250 °C. Hydrochloric acid is created by dissolving hydrogen chloride gas in water, resulting in a solution that is commonly marketed with a hydrogen chloride concentration of 28–35 percent.
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Where is hydrogen chloride used in industry or everyday life?
Hydrogen chloride (HCl) is used in various industrial and everyday applications. It is a compound of hydrogen and chlorine and exists as a gas at room temperature and pressure. A solution of hydrogen chloride gas in water is known as hydrochloric acid, which is widely utilized in industry and laboratories.
Industrially, hydrogen chloride is involved in the production of polyvinyl chloride (PVC), a widely used plastic. It is also used in the industrial processing of metals and the concentration of some ores.
In everyday life, hydrochloric acid is present in the digestive juices of the human stomach.
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hydrogen chloride (HCl), a compound of the elements hydrogen and chlorine, a gas at room temperature and pressure. A solution of the gas in water is called hydrochloric acid.
Hydrogen chloride may be formed by the direct combination of chlorine (Cl2) gas and hydrogen (H2) gas; the reaction is rapid at temperatures above 250 °C (482 °F). The reaction, represented by the equation H2 + Cl2 → 2HCl, is accompanied by evolution of heat and appears to be accelerated by moisture. Hydrogen chloride is commonly prepared both on a laboratory and on an industrial scale by the reaction of a chloride, generally that of sodium (NaCl), with sulfuric acid (H2SO4). It is also produced by the reaction of some chlorides (e.g., phosphorus trichloride, PCl3, or thionyl chloride, SOCl2) with water and as a by-product of the chlorination of many organic substances (e.g., methane or benzene).
Hydrochloric acid is prepared by dissolving gaseous hydrogen chloride in water. Because of the corrosive nature of the acid, ceramic, glass, or sometimes tantalum apparatus is commonly used. Hydrochloric acid is usually marketed as a solution containing 28–35 percent by weight hydrogen chloride, commonly known as concentrated hydrochloric acid. Anhydrous liquid hydrogen chloride is available, but because heavy and expensive containers are required to store it, the use of hydrogen chloride in this form is limited.
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Hydrogen chloride is a colourless gas of strong odour. It condenses at −85 °C (−121 °F) and freezes at −114 °C (−173 °F). The gas is very soluble in water: at 20 °C (68 °F) water will dissolve 477 times its own volume of hydrogen chloride. Because of its great solubility, the gas fumes in moist air. A water solution containing 20.24 percent by weight hydrogen chloride boils at 110 °C (230 °F) without change in composition (azeotropic mixture). In aqueous solution the compound is extensively dissociated into a hydronium ion (H3O+) and chloride ion (Cl−); in dilute solutions the dissociation is essentially complete. Thus, hydrochloric acid is a strong acid.
Gaseous hydrogen chloride reacts with active metals and their oxides, hydroxides, and carbonates to produce chlorides. These reactions occur readily only in the presence of moisture. Completely dry hydrogen chloride is very unreactive. The reactions of hydrochloric acid are those of typical strong acids, such as: reactions with metals in which hydrogen gas is displaced, reactions with basic (metal) oxides and hydroxides that are neutralized with the formation of a metal chloride and water, and reactions with salts of weak acids in which the weak acid is displaced. Hydrochloric acid also enters into chemical reactions characteristic of the chloride ion, such as reactions with various inorganic and organic compounds in which hydrochloric acid is used as a chlorinating agent and reactions with metals and their oxides in which complex chloride-containing ions are formed (e.g., with platinum, [PtCl6]2−, or with copper, [CuCl4]2−). The latter type of reaction accounts for the ease of solution of certain metals and metallic compounds in hydrochloric acid although they are slowly dissolved in other acids of equal strength (e.g., sulfuric or nitric acid). For this reason, hydrochloric acid is used extensively in the industrial processing of metals and in the concentration of some ores.
Hydrochloric acid is present in the digestive juices of the human stomach. Excessive secretion of the acid causes gastric ulcers, while a marked deficiency of it impairs the digestive process and is sometimes the primary cause of deficiency anemias. Exposure to 0.1 percent by volume hydrogen chloride gas in the atmosphere may cause death in a few minutes. Concentrated hydrochloric acid causes burns and inflammation of the skin.