Brief Explanation of Titration
Brief Explanation of Titration
Titration is the addition of an acidic solution to a basic solution or when you add a basic solution to an acidic solution. Titrations are used to determine the concentration of acids or bases in solution. An example of a titration is when a given volume of a solution of unknown acidity may be titrated with a base of known concentration until complete neutralization has occurred. This point is called the equivalence point and is generally determined by observing a color change in an indicator. From the volume and concentration of added base and the volume of acid solution, the unknown concentration of the solution before titration can be determined. Titrations can also be used to determine the number of acidic or basic groups in an unknown compound. A specific weight of the compound is titrated with a known concentration of acid or base until the equivalence point has been reached. From the volume and concentration of added acid or base and the initial weight of the compound, the equivalent weight, can be computed. Instead of adding an indicator to observe the equivalence point, you can construct a graph on which the pH at regular intervals is plotted along one axis and the number of moles of added acid or base at these intervals along the other axis. This kind of a plot is called a titration curve and is usually “S” shaped where the curve changes direction, corresponding to the equivalence point. From the pH at the equivalence point, the dissociation constant of the acidic or basic group can be determined. If a compound contains several different acidic or basic groups, the titration curve will show several “S” shaped curves like steps and the dissociation constant of each group can be obtained from the pH at its corresponding equivalence point.