Hydrochloric acid is a versatile chemical that hydrochloric acid is used in the chemical industry as a chemical reagent in the large-scale production of vinyl chloride (CH 2 CHCl) for PVC plastic, and polyurethane. However, it should be noted that there may be potential losses of the volatile metal chlorides (As, Sb, Sn, Se, Ge, and Hg) if HCl is used in acid digestion procedures. Hydrochloric acid can be effectively removed from sample solutions by repeated evaporation to incipient dryness with HNO 3 because the boiling point of the HCl azeotrope (110 ☌) is below that of the HNO 3 azeotrope (122 ☌). Unlike atomic absorption techniques, HCl is not a suitable sample matrix for ICP-MS analysis because chloride-bearing polyatomic ions cause major interferences (e.g., ArCl, ClO, and ClOH) with As and V ( 75As and 51V) and with many other trace elements (Cr, Fe, Ga, Ge, Se, Ti, and Zn) to a lesser extent ( Jarvis, 1992). HCl is the preferred acid medium to dissolve residues that remain after acid digestion or melts of alkali fusion for later analysis using atomic absorption spectrometry (AAS) ( Potts, 1987). At elevated temperatures and pressures, many silicates and other refractory oxides, sulfates, and fluorides are attacked by HCl to produce soluble salts. For silicate analysis, HCl is generally used in combination with other acids, such as HF and HNO 3, although some basic silicate minerals can be completely or partially decomposed by HCl alone. For example, due to its reducing properties and the complexing ability of Cl −, HCl is a better solvent for dissolving iron and manganese oxides than HNO 3.
It is an excellent solvent for carbonates, phosphates, many metal oxides, and metals. Unlike HNO 3, HCl is a weak reducing acid and is not generally used to digest organic materials. Qi, in Treatise on Geochemistry (Second Edition), 2014 15.5.2.1.4 Hydrochloric acidĬoncentrated hydrochloric acid (HCl) is the most frequently used halogen acid for the dissolution of geologic samples.
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