Hydrochloric Acid

Hydrochloric acid is a clear, colourless <a href="http://en.wikipedia.org/wiki/Solution" title="Solution" >solution</a> of <a href="http://en.wikipedia.org/wiki/Hydrogen_chloride" title="Hydrogen chloride" >hydrogen chloride</a> (<a href="http://en.wikipedia.org/wiki/Hydrogen" title="Hydrogen" >H</a><a href="http://en.wikipedia.org/wiki/Chlorine" title="Chlorine" >Cl</a>) in water. It is a highly <a href="http://en.wikipedia.org/wiki/Corrosive" title="Corrosive" class="mw-redirect" >corrosive</a>, <a href="http://en.wikipedia.org/wiki/Strong_acid" title="Strong acid" class="mw-redirect" >strong</a> <a href="http://en.wikipedia.org/wiki/Mineral_acid" title="Mineral acid" >mineral acid</a> with many industrial uses. Hydrochloric acid is found naturally in <a href="http://en.wikipedia.org/wiki/Gastric_acid" title="Gastric acid" >gastric acid</a>.

Historically called muriatic acid, and spirits of salt, hydrochloric acid was produced from <a href="http://en.wikipedia.org/wiki/Sulfuric_acid" title="Sulfuric acid" >vitriol</a> (sulfuric acid) and <a href="http://en.wikipedia.org/wiki/Sodium_chloride" title="Sodium chloride" >common salt</a>. It first appeared during the <a href="http://en.wikipedia.org/wiki/Renaissance" title="Renaissance" >Renaissance</a>, and then it was used by chemists such as <a href="http://en.wikipedia.org/wiki/Johann_Rudolf_Glauber" title="Johann Rudolf Glauber" >Glauber</a>, <a href="http://en.wikipedia.org/wiki/Joseph_Priestley" title="Joseph Priestley" >Priestley</a> and <a href="http://en.wikipedia.org/wiki/Humphry_Davy" title="Humphry Davy" >Davy</a> in their scientific research.

With major production starting in the <a href="http://en.wikipedia.org/wiki/Industrial_Revolution" title="Industrial Revolution" >Industrial Revolution</a>, hydrochloric acid is used in the <a href="http://en.wikipedia.org/wiki/Chemical_industry" title="Chemical industry" >chemical industry</a> as a <a href="http://en.wikipedia.org/wiki/Chemical_reagent" title="Chemical reagent" class="mw-redirect" >chemical reagent</a> in the large-scale production of <a href="http://en.wikipedia.org/wiki/Vinyl_chloride" title="Vinyl chloride" >vinyl chloride</a> for <a href="http://en.wikipedia.org/wiki/Polyvinyl_chloride" title="Polyvinyl chloride" >PVC</a> plastic, and <a href="http://en.wikipedia.org/wiki/Methylene_diphenyl_diisocyanate" title="Methylene diphenyl diisocyanate" >MDI</a>/<a href="http://en.wikipedia.org/wiki/Toluene_diisocyanate" title="Toluene diisocyanate" >TDI</a>for <a href="http://en.wikipedia.org/wiki/Polyurethane" title="Polyurethane" >polyurethane</a>. It has numerous smaller-scale applications, including household <a href="http://en.wikipedia.org/wiki/Cleaning" title="Cleaning" class="mw-redirect" >cleaning</a>, production of<a href="http://en.wikipedia.org/wiki/Gelatin" title="Gelatin" >gelatin</a> and other <a href="http://en.wikipedia.org/wiki/Food_additive" title="Food additive" >food additives</a>, <a href="http://en.wikipedia.org/wiki/Descaling" title="Descaling" class="mw-redirect" >descaling</a>, and <a href="http://en.wikipedia.org/wiki/Leather" title="Leather" >leather</a> processing. About 20 million <a href="http://en.wikipedia.org/wiki/Tonne" title="Tonne" >tonnes</a> of hydrochloric acid are produced annually.