acid

Pronunciation key ( as′id )

ac•id

adj.

[L. acidus, sour < base ac-, sharp].

1. Sour; sharp and biting to taste; tart.
2. Substance that dissociates, releasing hydrogen (H^-) ions but not hydroxyl (OH⁺) ions, having a pH of less than 7. see base.
3. In chemistry, a compound that can react with a base to form a salt, the hydrogen of the acid being replaced by a positive ion; according to modern theory, a compound yielding hydrogen ions (protons) to a base in a chemical reaction: in water solution, an acid tastes sour, turns blue litmus red, and, according to the dissocation theory it produces free hydrogen ions.

Syn. SOUR

References

Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1971

Webster's New World Dictionary of the American Language (College Edition) ©1955