hydrochloric acid

hydrochloric acid
IUPACName	Hydrogen chloride
OtherNames	Muriatic acid
Formula	HCl (aqueous)
CASNumber	7647-01-0
Appearance	Colorless to slightly yellow liquid
Density	1.18 g·cm−3 (conc.)
BoilingPoint	110 °C (approx. for concentrated solutions)

hydrochloric acid Hydrochloric acid is the aqueous solution of hydrogen chloride and a widely used inorganic acid in chemistry and industry. It has been central to developments in industrial revolution era manufacturing, influenced policies of Ottoman Empire trade in salts, featured in experiments by Antoine Lavoisier, and appears in modern standards set by organizations such as International Organization for Standardization and American Chemical Society. Concentrated solutions are corrosive and handled under regulations like those from Occupational Safety and Health Administration and directives from the European Union.

Introduction

Aqueous hydrogen chloride, commonly called hydrochloric acid in practice, functions as a strong monoprotic acid and has intensive use across sectors governed by bodies such as United Nations's chemical conventions, World Health Organization, Food and Drug Administration, and national agencies like Health Canada. Historical production methods trace through innovations by chemists including Joseph Priestley and industrialists connected to firms such as BASF and Dow Chemical Company, while control measures intersect with treaties like the Chemical Weapons Convention and standards from British Standards Institution.

Chemical Properties and Preparation

Hydrochloric acid exhibits characteristic properties described in compilations by Royal Society of Chemistry, National Institute of Standards and Technology, and texts by authors associated with Cambridge University Press and Wiley. As an aqueous solution of hydrogen chloride gas originally isolated in experiments by Carl Wilhelm Scheele and studied by Humphry Davy, it is a strong electrolyte that fully dissociates into H+ and Cl− in water, behavior tabulated in handbooks used by Massachusetts Institute of Technology and Imperial College London. Laboratory preparation commonly involves dissolving hydrogen chloride from gas generators such as setups referenced in manuals from Sigma-Aldrich and procedures standardized by American Society for Testing and Materials. Related reactions include acid–base titrations documented in works from John Dalton era compilations and modern protocols endorsed by Royal Society publications.

Occurrence and Applications

Hydrochloric acid appears in industrial streams of companies like Shell plc and ExxonMobil, and is integral to processes described in texts from McGraw-Hill and standards used by American Institute of Chemical Engineers. It is employed in pickling operations in facilities modeled after practices at Bethlehem Steel and in cleaning sequences used historically by firms such as General Electric. Analytical chemistry applications are detailed in compendia from Merck and laboratories at Stanford University, Harvard University, and Yale University. In construction and mining contexts, its role is cited in case studies involving infrastructure projects overseen by entities like World Bank and International Monetary Fund funding.

Biological Role and Safety

Physiologically, gastric acid in humans is predominantly a solution of hydrogen chloride secreted by parietal cells studied in research from Mayo Clinic, Johns Hopkins University, and the National Institutes of Health. Clinical guidelines from American Gastroenterological Association and European Society of Gastroenterology address disorders linked to altered acid secretion, with therapies developed by pharmaceutical companies like Pfizer and GlaxoSmithKline. Safety data sheets from agencies including Centers for Disease Control and Prevention and Environmental Protection Agency outline exposure controls used in laboratories at institutions such as Massachusetts General Hospital and Cleveland Clinic. Occupational limits and protective equipment recommendations are published by Occupational Safety and Health Administration and NIOSH.

Industrial Production and Uses

Large-scale production methods are practiced by corporations such as Solvay and AkzoNobel and described in industrial chemistry handbooks from Wiley-VCH. Major uses include metal pickling in plants once operated by U.S. Steel, acidifying brine in chlorine production units associated with companies like Chlorine Institute members, and pH control in water treatment facilities employed by municipal systems cited in reports from American Water Works Association. Manufacture of organic compounds, regeneration of ion exchangers, and digestion in food processing are detailed in manuals used by Nestlé and Kraft Foods. Distribution and storage practices follow guidance issued by regulatory bodies like Transportation Security Administration and International Maritime Organization.

Environmental Impact and Regulation

Environmental considerations are governed by frameworks including United Nations Environment Programme conventions, emissions reporting under Kyoto Protocol-era instruments, and national laws such as statutes enforced by Environmental Protection Agency and regulatory agencies in the European Commission. Acidic effluents from industries are monitored in programs administered by organizations like Natural Resources Defense Council and remediation techniques are implemented in projects contracted by firms such as Bechtel and Jacobs Engineering. International incident responses reference protocols similar to those coordinated by International Maritime Organization and disaster planning by Federal Emergency Management Agency.

Category:Acids