Introduction
Even if a person has never studied chemistry in-depth or been to a chemistry lab, he or she might still be familiar with the concepts discussed in this essay – acids, bases, and buffers. These substances are commonly used in everyday life: for instance, it is safe to assume that almost everyone has drunk orange juice, an acidic solution, or use baking soda, a basic solution. This paper will describe each of the elements in detail, outline the differences between them, and provide ideas for their implementation.
Acid and Base
Ionization of Water
The main difference between acidic and basic solutions is the concentration of hydrogens ions (H+): for the former, it is higher than that of pure water, and for the latter, it is lower. Autoionization of water is a spontaneous process characterized by the dissociation of a certain percentage of water molecules (Starr, Taggart, & Evers, 2018). The equation that illustrates the described mechanism looks as follows:
H20 -> <- H+ +OH-
From the equation, it is possible to conclude that autoionization results in equal numbers of hydrogen ions (H+) and hydroxide ions (OH-). Hydroxide ions are free-floaters: they can move unimpeded without making any bounds. This is not the case for hydroxide ions: they are transferred directly to the closest water molecule around to build hydronium ions (H30). In the end, there are no free-floating hydrogen ions left. Yet, it is a general scientific consensus to refer to their concentration as if they were separate and not in hydronium form.
Acid
The pH scale runs from 0 to 14 and measures the concentration of hydrogen ions. The end result is calculated through the negative logarithm of the hydrogen ion concentration. On this scale, values between 0 and 7 indicate acids. Acids give foods and edible products that contain them a sour taste – a good example would be lemon and vinegar. If metal is immersed in an acidic solution, it will trigger a reaction with hydrogen ions, which will float to the surface and make bubbles. The last characteristic is acid’s ability to turn a blue litmus indicator red.
Acidic solutions are the best choice for a process called pickling – rust and corrosion removal from metal surfaces. Wet cell batteries have acidic elements – in them, acids play the role of an electrolyte, for instance, sulfuric acid in car batteries. Sulfuric acid belongs to the stronger subgroup of the discussed element and is widely used in mineral processing. Phosphate fertilizers used in agriculture and gardening are the product of the reaction between phosphate minerals and sulfuric acid.
Base
On the pH scale, values above neutral – from 7 to 14 – indicate base. As opposed to acids, bases taste bitter and turn a litmus indicator from blue to red. If a person runs a basic solution through his or her fingers, it combines with fatty acids on the human skin. As a result, bases feel slimy and slippery to the touch. When dissolved in water, bases increase the hydroxide concentration.
Aluminum hydroxide can neutralize stomach acid, and for this reason, it is widely used as an antacid in the healthcare industry. People who suffer from excessive stomach acid are familiar with such commercial antacids as Di-Gel, Gelusil, and Maalox, each of which contains aluminum hydroxide. Its relative, aluminum hydroxy chloride, is known for its ability to close pores and stop sweating, which makes it irreplaceable in the production of commercial antiperspirants. Lastly, probably, the best knowledge base is baking soda (sodium bicarbonate). The product of its reaction to acid is carbon dioxide which helps the dough to rise. Another common home use is putting baking soda in the refrigerator for some time to let it absorb unpleasant smells.
Buffer
Buffers neutralize small amounts of acid and base and, hence, maintain the pH balance of the solution. They are important for processes and reactions which require pH to be stable or stay within a particular range. Buffer solutions are characterized by a working pH range and capacity which indicates how much acid or base it can neutralize. Buffers are widely used in everyday life: for instance, baby lotions that prevent rash and the growth of bacteria are buffered to keep the pH of 6. Laundry detergents often contain buffers that prevent its ingredients from breaking down.
Conclusion
Two concepts, autoionization of water and the pH scale, are central to understanding what acids, bases, and buffers are. Water is capable of spontaneous ionization, and the concentration of hydrogen ions indicates whether the substance is going to basic or acidic. For a substance to be considered acidic, it needs to score less than neutral on the pH scale; basic solutions score more than neutral. Buffers moderate the pH range of a solution and can neutralize added acids or bases. All three elements are characterized by broad industrial and household use.
Reference
Starr, C., Taggart, R., & Evers, C. (2018). Biology:The unity and diversity of life (15th ed.). Boston, MA: Cengage Learning.