Unlike nonelectrolytes, electrolytes contain dissolved ions that enable
them to easily conduct electricity.
LEARNING OBJECTIVE [ edit ]
Recognize the properties of an electrolyte solution.
KEY POINTS [ edit ]
Electrolytes are salts or molecules that ionize completely insolution. As a result, electrolyte
solutions readily conduct electricity.
Nonelectrolytes do not dissociate into ions in solution; nonelectrolyte solutions do not,
therefore, conduct electricity.
TERMS [ edit ]
salt
An ionic compound composed of cations and anions that are held together by electrostatic
attraction.
solute
Any substance that is dissolved in a liquid solvent to create a solution.
solution
A homogeneous mixture, which may be a liquid, gas, or solid, formed by dissolving one or more
substances.
nonelectrolyte
A substance that does not dissociate into ions when in solution.
electrolyte
A substance that dissociates into ions when in solution.
Give us feedback on this content: FULL TEXT [ edit ]
Electrolyte Solutions
An electrolyte is any salt or ionizable molecule that, when dissolved in solution, will give that
solution the ability to conduct electricity. This is because when a salt dissolves, its
dissociated ions can move freely in solution, allowing a charge to flow.
Electrolyte solutions are normally formed when a salt is placed into a solvent such as water.
For example, when table salt, NaCl, is placed in water, the salt (a solid) dissolves into its
component ions, according to the dissociation reaction:
NaCl(s) → Na+(aq) + Cl−(aq)
It is also possible for substances to react with water to yield ions in solution. For example,
carbon dioxide gas, CO2, will dissolve in water to produce a solution that contains hydrogen
ions, carbonate, and hydrogen carbonate ions:
2 CO2(g)+ 2 H2O(l) → 3 H+(aq) + CO32­(aq) + HCO3­(aq)
The resulting solution will conduct electricity because it contains ions. It is important to keep
in mind, however, that CO2 is not an electrolyte, because CO2 itself does not dissociate into
ions. Only compounds that dissociate into their component ions in solution qualify as
electrolytes.
Strong and Weak Electrolytes
As mentioned above, when an ionizable solute dissociates, the resulting solution can conduct
electricity. Therefore, compounds that readily form ions in solution are known
asstrong electrolytes. (By this reasoning, all strong acids and strong bases are strong
electrolytes.)
By contrast, if a compound dissociates to a small extent, the solution will be a
weak conductor of electricity; a compound that only dissociates weakly, therefore, is known
as a weak electrolyte.
A strong electrolyte will completely dissociate into its component ions in solution; a weak
electrolyte, on the other hand, will remain mostly undissociated in solution. An example of a
weak electrolyte is acetic acid, which is also aweak acid.
Gatorade as an electrolyte solution
The sports drink Gatorade advertises that it contains electrolytes because it contains sodium, potassium,
magnesium, and other ions. When humans sweat, we lose ions necessary for vital bodily functions; to
replenish them, we need to consume more ions, often in the form of an electrolyte solution. In the human
body, electrolytes have many uses, including helping neurons conduct electrical impulses.
Nonelectrolyte Solutions
Nonelectrolytes are compounds that do not ionize at all in solution. As a result, solutions
containing nonelectrolytes will not conduct electricity. Typically, nonelectrolytes are
primarily held together by covalent rather than ionic bonds. A common example of a
nonelectrolyte is glucose, or C6H12O6. Glucose (sugar) readily dissolves in water, but because
it does not dissociate into ions in solution, it is considered a nonelectrolyte; solutions
containing glucose do not, therefore, conduct electricity.