One of the basic methods of analytical chemistry is titration. Titration is the
incremental addition of a titrant into a known volume of titrating fluid in the presence of
an indicator that identifies the neutralization point. Titration is based on the following
principle: "One equivalent weight of a substance will react exactly with one equivalent
weight of another substance." Equivalent weight refers to the reacting ability of a
substance. When performing a titration, the concentration of the solutions involved
MUST be expressed in terms of the concentration units that indicate reacting strength,
Eq/L or mEq/L.
a. The number of equivalents or milliequivalents present in a given volume of
solution indicates the reacting strength of a solution. Since titration is based on the
reacting strength of one solution versus the reacting strength of another solution
(usually an acid versus a base), the Eq/L concentration of the acid times the volume of
the acid is equal to the Eq/L concentration of the base times the volume of the base. A
familiar formula that states these facts is:
C1V1 = C2V2
C1 = Eq/L or mEq/L concentration of the acid
V1 = Volume of the acid
C2 = Eq/L or mEq/L concentration of the base
V2 = Volume of the base
It is not crucial that the variables follow the above format. However, it is
crucial that the appropriate concentration and volume be multiplied.
b. Associated Terms Follow:
(1) Acidimetry. Acidimetry is defined as the determination of the
concentration of an unknown acid by using a standard base (a base in which the exact
concentration is known).
(2) Alkalimetry. Alkalimetry is defined as the determination of the
concentration of an unknown base by using a standard acid.