Answer:
HCl causes local pH changes and denatures proteins
Explanation:
Hydrochloric acid (HCl, also known as muriatic acid) is a colorless corrosive, strong mineral acid with many industrial uses among which, when it reacts with an organic base it forms a hydrochloride salt.
Concentrated hydrochloric acid (HCl) is the most frequently used halogen acid for the dissolution of geologic samples. Unlike HNO3, HCl is a weak reducing acid and is not generally used to digest organic materials. It is an excellent solvent for carbonates, phosphates, many metal oxides, and metals. 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 HNO3. For silicate analysis, HCl is generally used in combination with other acids, such as HF and HNO3, although some basic silicate minerals can be completely or partially decomposed by HCl alone. At elevated temperatures and pressures, many silicates and other refractory oxides, sulfates, and fluorides are attacked by HCl to produce soluble salts. 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). 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). Hydrochloric acid can be effectively removed from sample solutions by repeated evaporation to incipient dryness with HNO3 because the boiling point of the HCl azeotrope (110 °C) is below that of the HNO3 azeotrope (122 °C). 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.
