Chemistry Reference
In-Depth Information
16. Chloride Levels
Topic
Levels of chloride ions in water samples can be measured.
Introduction
Do you ever wonder what is in your drinking water? Chances are, even
if you are drinking water that has been purified and disinfected, it still
contains traces of minerals and chemicals that were either obtained from
the environment or added to the water to kill bacteria. Chloride ions are
just one of several substances that are commonly found in water. The
element chlorine occurs naturally in the environment in compounds or as
chlorine gas. Chlorine is highly reactive in its natural state, so it generally
forms
ionic bonds
with other atoms to create compounds. When ionic
compounds such as sodium chloride (NaCl) dissolve in water, they break
down into their respective
ions
, which in the case of sodium chloride are
Na
+
and Cl
−
. Figure 1 shows how individual ions are surrounded by water
molecules and separated from each other. Chloride makes its way into
waterways in two ways: from the natural breakdown of chloride-containing
minerals and from the addition of chlorine to water as a disinfecting agent.
Generally, small doses of chloride in water are not considered harmful.
Some people do not like the taste of chloride in their water, but it is fairly
rare for individuals to suffer illness due to the intake of small amounts of
this ion. However, large quantities of chloride can cause health problems.
Some studies have shown that the presence of chloride ions correlates to
disorders with the immune system, cardiovascular system, and respiratory
system. Other research indicates that chloride ions, when combined
with organic compounds that occur naturally in the environment, create
substances that can cause cancer. Therefore, detecting and measuring
chloride in water is important. In this experiment, you will test three
different samples of water for the presence of chloride ions by titrating the
samples with silver nitrate.
Time Required
60 minutes
