By Inkjet Insight / Published:

A substance that yields hydrogen (H+) ions when added to a solution. Acids typically have a corrosive effect on many substances. The acidity of a solution is described in terms of pH, a scale running from 1:14, where 7 is defined as neutral, with acidity increasing as pH decreases. Acids turn litmus paper red, and neutralize alkalis, those substances occupying the opposite end of the pH scale. A substance capable of functioning both as an acid an an alkali is referred to as amphoteric. See pH.