Answer: An acid is a chemical that dissociates, releasing free hidrogen H+ ions.
Explanation:
The word acid originates from the Latin acidus, which means sour or astringent. Arrhenius's definition of an acid is a substance that, in aqueous solution, yields H + ions (aq). The strength of an acid corresponding is its greatest tendency to donate a proton, while the strength of a base is measured by its tendency to receive a proton.
Quantitatively the relative forces of acids and bases can be measured and adjusted to an appropriate scale. The strength of an acid, ie its degree of dissociation in solution, is indicated by the magnitude of its dissociation constant. Therefore, the weaker the acid, the lower its dissociation constant.
