e. Electrolyte. When a substance dissociates to a fair extent in water, it will
produce enough ions to support an electric current. We can use this property to
differentiate between substances that are molecular and substances that are ionic in
solution. An electrolyte is a substance, which dissociates sufficiently in solution to carry
an electric current. It is therefore ionic in nature (figure 2-1).
f. Non-Electrolyte. A substance that does not dissociate or carry an electric
current in solution is called a non-electrolyte.
g. Hydrolysis. Some compounds form ions in solution by reacting with water.
This reaction with water is called hydrolysis. Hydrolysis is the dissociation of a
compound through the splitting and incorporation of water. Hydrolysis occurs when
acidic, basic, or neutral (weak acid/weak base) salts are dissolved in water. Consider,
for example, the basic salt, sodium bicarbonate.
NaHCO3 + H2O ---> Na+ + HCO3 - + H2O ---> Na+ + OH- + H2CO3
The hydroxyl ion from water is associated with the sodium ion from the salt. The
hydrogen ion from water is associated with the bicarbonate radical, and these two exist
primarily as undissociated carbonic acid. The net result of this hydrolysis reaction is a
basic solution containing sodium and hydroxyl ions and undissociated carbonic acid.
Figure 2-1. Flow of electric current through electrolyte solution.