hydrochloric acid

noun1

1. •
   A strong acid made by dissolving the gas hydrogen chloride in water. It reacts with alkalis, bases and many metals to form chlorides; it has many industrial applications.

   • If not sufficiently purified, a little hydrochloric or oxalic acid, or caustic potash may be put in the water, according as the stains are from grease or from ink. — 1880