Properties and Reactions of Acids and Bases

Acids and bases have distinctive, testable properties that follow directly from the ions they produce in solution. Acids taste sour (although tasting laboratory chemicals is never appropriate), turn blue litmus red, have a pH below 7, and conduct electricity because they release mobile ions. Bases, and especially their soluble form (alkalis), taste bitter, feel slippery, turn red litmus blue, and have a pH above 7. An alkali is simply a base that is soluble in water and therefore releases hydroxide ions into solution; all alkalis are bases, but not all bases are alkalis. Copper(II) oxide, for instance, is a base because it neutralizes acids, yet it is insoluble and so is not an alkali.

The characteristic reactions of acids are among the most useful in the whole course, and you should be ab