acid A chemical capable of donating a hydron (proton,
H+) or capable of forming a covalent bond with an elec-
tron pair. An acid increases the hydrogen ion concentra-
tion in a solution, and it can react with certain metals,
such as zinc, to form hydrogen gas. A strong acid is a
relatively good conductor of electricity. Examples of
strong acids include hydrochloric (muriatic), nitric, and
sulfuric, while examples of mild acids include sulfurous
and acetic (vinegar). The strength of an acidic solution is
usually measured in terms of its pH (a logarithmic func-
2abstractiontion of the H+ ion concentration). Strong acid solutions
have low pHs (typically around 0–3), while weak acid
solutions have pHs in the range 3–6.
