$$\textbf{Concept:}$$ Acid: A solution that has an excess of H+ ions. It comes from the Latin word acidus, which means "sharp" or "sour". Base: A solution that has an excess of OH- ions. Another word for the base is alkali.
$$\bullet$$ Acid: A solution that has an excess of H+ ionsMain means the main constituent of acid is the H+ ion