characteristics. They have there own unique traits, acids taste sour, turn litmus red while
bases taste bitter and turn litmus blue. The term pH relates to measuring the acidity or
alkalinity of a solution, such as vinegar, or even a damp substance like soul.
The neutral pH is 7, which is essentially water, with lower numbers indicating acidity and
higher numbers indicating alkalinity. Hydronium ions (H3O+) are formed when water
molecules (H2O) bond with hydrogen ions (H+). Hydronium ions are positively charged
because of their extra hydrogen ion. Hydroxide ions (OH-) are produced when water
molecules (H2O) ionize to become hydronium ions (H3O+) and hydroxide ions (OH-).
Substances with a high concentration of hydroxide ions are bases. Bases have a pH rating
of seven or higher. Solutions of ions conduct an electric current, similar in the way that
wire does. Ions can move about in a solution and carry a charge. If they can do carry the
charge they are electrolytes.
The Bronsted-Lowry theory states that an acid is a proton donor and a base a
proton acceptor. Although the acid must still contain hydrogen, the Bronsted-Lowry
theory does not require an aqueous medium. The Bronsted-Lowry definition of acids and
bases also explains why a strong acid displaces a weak acid from its compounds and
likewise for strong and weak bases. In the Lewis theory of acid-base reactions, bases
donate pairs of electrons and acids accept pairs of electrons. A Lewis acid is any
substance, such as the H+ ion, that can accept a pair of nonbonding electrons. Therefore, a
Lewis acid is an electron-pair acceptor. A Lewis base is any substance, such as the OH-
ion, that can donate a pair of nonbonding electrons. A Lewis base is therefore an
Svante Arrhenius was a Swedish chemist who helped lay the foundation of
modern day chemistry. When he was a student, he studied the conductive properties of
electrolytic solutions. In his doctoral thesis he made the theory of electrolytic
dissociation. This theory implies that in electrolytic solutions, the dissolved chemical
compounds in the solution are dissociated into ions, even when there is no current
flowing through the solution. Initially, his theory was thought to be wrong, and his thesis
was given the lowest possible passing grade. However, later on Arrhenius' theory of
electrolytic dissociation became generally accepted, and eventually became one of the
principles of modern chemistry.
The pH scale measures the concentration of H+ and OH-. The pH scale was
developed because the concentration of the solution can vary by many factors over time,
and a pH scale was the easiest way to express the variation of the solution. The pH scale
ranges from 0 to 14. The 0 end of the scale is where the concentration is acidic. After 7 the
concentration starts to become more basic as it increases. Most biological fluids are between
pH 6 and pH 8, and there are a few exceptions to this like stomach acid. Each pH unit
represents a tenfold difference of the H+ and OH- concentration. This makes the pH scale so
compact. A solution of pH 2 is not twice as acidic as a solution of pH 4, but a thousand times
more acidic. So when the pH of a solution changes slightly, it actually changes the
concentrations of H+ and OH- in a large way.
Antacids are drugs that diminish abnormal acidity in the digestive tract or in the
other organs. Those that unite directly with free acid in the stomach are known as direct
antacids. "Remote" antacids, such as the acetates, citrates, and tartrates of the alkalies, act
by being changed into carbonates, thus increasing the alkalinity of the blood. Essentially
you are lowering the acidity in your body by adding a base.
The strength of acids and bases depends on their...