Compounds in this group are generally nonflammable.

Strong, non-oxidizing acids are generally soluble in water with the release of hydrogen ions. The resulting solutions have pHs of 1 or close to it. Acids neutralize chemical bases (for example: amines and inorganic hydroxides) to form salts. Neutralization occurs as the base accepts hydrogen ions that the acid donates. Neutralization can generate dangerously large amounts of heat in small spaces. The dissolution of acids in water or the dilution of their concentrated solutions with additional water may generate significant heat; the addition of water often generates sufficient heat in the small region of mixing to cause some of the water to boil explosively. The resulting "bumping" spatters the acid. These materials react with active metals, including such structural metals as aluminum and iron, to release hydrogen, a flammable gas. They can initiate the polymerization of certain classes of organic compounds. They react with cyanide compounds to release gaseous hydrogen cyanide. They often generate flammable and/or toxic gases in contact with dithiocarbamates, isocyanates, mercaptans, nitrides, nitriles, sulfides, and strong reducing agents. Additional gas-generating reactions occur with sulfites, nitrites, thiosulfates (to give H2S and SO3), dithionites (SO2), and even carbonates: the carbon dioxide gas from the last is non-toxic but the heat and spattering from a rapid reaction can be troublesome. Acids often catalyze (increase the rate of) chemical reactions.

Corrosive to tissue. Acid fumes irritate sensitive tissues (such as the eyes and respiratory system) especially severely.

Acids have a sour taste; they turn blue litmus red. Strong acids completely dissociate in water to H+ ions and extremely weak conjugate base anions. Non-oxidizing acids give anions that do not act as oxidants. They possess a pKa value less than -2, or a pH value less than 2.

Hydrochloric acid, hydroiodic acid, hydrobromic acid.