Products
Hydrochloric acid is available in various concentrations at specialty stores.
Structure and properties
Hydrochloric acid is the name given to an aqueous solution of hydrogen chloride gas (HCl). Concentrated hydrochloric acid exists as a clear, colorless liquid that fumes in air with a pungent odor and is miscible with water. It has a concentration of 36% (m/m) and is slightly heavier than water. Various dilutions exist, for example, hydrochloric acid 25% (PH) or dilute hydrochloric acid 10% (PhEur). Hydrogen chloride forms from elemental chlorine and hydrogen in the explosive chlorine oxyhydrogen reaction:
- H2 (hydrogen) + Cl2 (chlorine gas) 2 HCl (hydrogen chloride)
This reaction is initiated by heating or photochemically. Hydrochloric acid can also be produced with sulfuric acid and sodium chloride.
Effects
Hydrochloric acid has strong corrosive and acidic properties. In pharmacy, it is used for the preparation of active ingredient salts, hydrochlorides. In this process, a basic group in the active ingredient is protonated and positively charged. The chloride ion acts as a counterion. Numerous active ingredients exist as hydrochlorides, for example alfuzosin or cetirizine. Hydrochloric acid is a component of gastric juice and is secreted by the gastric vestibular cells. It is important for digestion, as protection against pathogens, and for the absorption of nutrients.
Indications for use
- For the preparation of active ingredient salts (chlorides and hydrochlorides).
- For chemical syntheses, as a reagent and to adjust the pH, as an excipient.
- As a cleaning agent, for example, for cleaning crystals or as a descaler.
- The hydrochloric acid was formerly used in sufficient dilution (!) For the treatment of a reduced or absent gastric acid formation.
Adverse effects
Concentrated solutions have strong corrosive properties. They can cause severe burns to the skin, severe eye damage and irritation of the respiratory tract if used improperly. It is therefore essential that the precautionary measures in the safety data sheet are strictly observed. When working with hydrochloric acid, gloves, protective clothing, eye protection and face protection should be worn. The work should be carried out under the fume hood, because the vapors are also dangerous. In case of accidental contact with skin or eyes, rinse sufficiently with water and consult a doctor. When mixing with other chemicals and detergents, the toxic chlorine gas may be released, for example, together with Javel water.
