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Acids and bases are chemical compounds always present in our daily life. They are important raw materials in manufacturing industries and are necessary for the control of various industrial processes. They participate actively in living organisms’ metabolism and, if improperly disposable they can alter the environmental conditions necessary to the human well-being. Acids have sour taste (e.g. citrus fruits), while bases have astringent flavors (“soap like”). In addition, theses substances are part of cosmetic formulations, food, drinks, pharmaceuticals, cleaning products, toiletries, etc.. The most common way to determine the acidity or alkalinity of an aqueous solution is measuring its pH, but this concept is not as simple as it seems to be.

acids, bases, acid-base theories, pH, the concept of pH, pH scale, acidity, alkalinity.

João Carlos de Andrade
Universidade Estadual de Campinas, Instituto de Química