4780. Hydrochloric Acid

Properties

Fumes in air. Corrosive. May be colored yellow by traces of iron, chlorine, and organic matter. Reagent grade concd hydrochloric acid contains close to 38.0% HCl. 83 ml of concd HCl poured into sufficient water to make 1 liter yields approx 1.0N HCl. The pH of 1.0N HCl is 0.10; of 0.1N = 1.10; of 0.01N = 2.02; of 0.001N = 3.02; of 0.0001N = 4.01. n_D¹⁸ (1.0N soln) 1.34168. d₄¹⁵ 1.05 (10.17% w/w soln); 1.10 (20%); 1.15 (29.57%); 1.20 (39.11%). Freezing pt: 17.14° (10.81% soln); 62.25° (20.69%); 46.2° (31.24%); 25.4° (39.17%), Gmelins, Chlorine (8th ed.) 6, 136-137 (1927). Constant boiling azeotrope with water bp₇₆₀ 108.58° contg 20.22% HCl, d₄¹⁵ 1.096. Boiling weaker or stronger aq solns results in loss of either component until the constant boiling acid is obtained.

Caution

Corrosive burns may result from the inhalation of acid fumes and from skin contact with or the ingestion of strong acid. Symptoms after ingestion or skin contact include immediate pain and ulceration of all membranes and tissues which come in contact with the acid. Ingestion may be associated with nausea, vomiting and intense thirst; corrosion of the stomach may lead within a few hours or a few days to gastric perforation and peritonitis. Late esophageal, gastric and pyloric strictures and stenoses should be anticipated. Contact of conc acid with the eye can cause extensive necrosis of the conjunctiva and corneal epithelium, resulting in perforation or opaque scarring. Chemical pneumonitis can be expected after respiratory exposure to acid vapors or after tracheobronchial aspiration of ingested acid. Death may occur due to complications such as circulatory shock, asphyxia due to glottic or laryngeal edema, perforation of the stomach with peritonitis, gastic hemorrhage, infection or anition due to stricture formation. See: Clinical Toxicology of Commercial Products, R. E. Gosselin et al., Eds. (Williams & Wilkins, Baltimore, 5th ed., 1984) Section III, pp 8-11.