soluble in water. HCl (g) + H O (l) H O + + Cl - Chemical properties: Like all acids it liberates hydrogen gas from metals and carbon dioxide from carbonate and bicarbonate salts. Zn + 2HCl ZnCl + H Mg + 2HCl MgCl + H Na CO + 2HCl 2NaCl + CO + H O CaCO + 2HCl CaCl + CO + H O NaHCO + 2HCl 2NaCl + CO + H O It liberates sulphur dioxide from sodium sulphite Na SO + 2HCl 2NaCl + H O + SO When three parts of concentrated hydrochloric acid and one part of concentrated nitric acid are mixed, Aquaregia (Royal water) is obtained. This is used for dissolving gold, platinum etc...
XII XII - - - - Au + 4H + + NO - + Cl- AuCl - + NO + 2H O 3Pt + 16H + + 4NO - + 18Cl- [PtCl ] - + 4NO + 8H O Uses of hydrochloric acid: . Hydrochloric acid is used for the manufacture of chlorine, ammonium chloride, glucose from corn starch etc., . It is used in the extraction of glue from bone and also for purification of bone black . .
Trends in physical and chemical properties of hydrogen halides: Preparation: Direct combination is a useful means of preparing hydrogen chloride. The reaction between hydrogen and fluorine is violent while the reaction between hydrogen and bromine or hydrogen and iodine are reversible and don’t produce pure forms. Displacement reactions: Concentrated sulphuric acid displaces hydrogen chloride from ionic chlorides. At higher temperatures the hydrogen sulphate formed react with further ionic chloride.
Displacement can be used for the preparation of hydrogen fluorides from ionic fluorides. Hydrogen bromide and hydrogen iodide are oxidised by concentrated sulphuric acid and can’t be prepared in this method. Hydrolysis of phosphorus trihalides: Gaseous hydrogen halides are produced when water is added in drops to phosphorus tri