Science Explorer. Multimedia Gallery. Park Passes. Technical Announcements. Employees in the News. Emergency Management. Survey Manual. Water and electricity don't mix, right? Well actually, pure water is an excellent insulator and does not conduct electricity. The thing is, you won't find any pure water in nature, so don't mix electricity and water. Our Water Science School page will give you all the details.
You're never too old to learn something new. All my life I've heard that water and electricity make a dangerous pair together. And pretty much all of the time that is true—mixing water and electricity, be it from a lightning bolt or electrical socket in the house, is a very dangerous thing to do.
But what I learned from researching this topic was that pure water is actually an excellent insulator and does not conduct electricity. Water that would be considered "pure" would be distilled water water condensed from steam and deionized water used in laboratories , although even water of this purity can contain ions.
But in our real lives, we normally do not come across any pure water. If you read our article about water being the " universal solvent " you know that water can dissolve more things than just about any other liquid. Water is a most excellent solvent. It doesn't matter if the water comes out of your kitchen faucet, is in a swimming pool or dog dish, comes out of the ground or falls from the sky, the water will contain significant amounts of dissolved substances, minerals, and chemicals.
The reduction of the electrostatic attraction permits the independent motion of each hydrated ion in a dilute solution, resulting in an increase in the disorder of the system as the ions change from their fixed and ordered positions in the crystal to mobile and much more disordered states in solution. This increased disorder is responsible for the dissolution of many ionic compounds, including KCl, which dissolve with absorption of heat. In other cases, the electrostatic attractions between the ions in a crystal are so large, or the ion-dipole attractive forces between the ions and water molecules are so weak, that the increase in disorder cannot compensate for the energy required to separate the ions, and the crystal is insoluble.
Such is the case for compounds such as calcium carbonate limestone , calcium phosphate the inorganic component of bone , and iron oxide rust. Water ionizes when one molecule of water gives up a proton to another molecule of water, yielding hydronium and hydroxide ions.
In some cases, we find that solutions prepared from covalent compounds conduct electricity because the solute molecules react chemically with the solvent to produce ions.
For example, pure hydrogen chloride is a gas consisting of covalent HCl molecules. This gas contains no ions.
However, when we dissolve hydrogen chloride in water, we find that the solution is a very good conductor. The water molecules play an essential part in forming ions: Solutions of hydrogen chloride in many other solvents, such as benzene, do not conduct electricity and do not contain ions. Likewise, weak acids and bases that only react partially generate relatively low concentrations of ions when dissolved in water and are classified as weak electrolytes.
The reader may wish to review the discussion of strong and weak acids provided in the earlier chapter of this text on reaction classes and stoichiometry. Substances that dissolve in water to yield ions are called electrolytes.
Electrolytes may be covalent compounds that chemically react with water to produce ions for example, acids and bases , or they may be ionic compounds that dissociate to yield their constituent cations and anions, when dissolved. Dissolution of an ionic compound is facilitated by ion-dipole attractions between the ions of the compound and the polar water molecules.
Soluble ionic substances and strong acids ionize completely and are strong electrolytes, while weak acids and bases ionize to only a small extent and are weak electrolytes. 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:. 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:.
The resulting solution will conduct electricity because it contains ions. It is important to keep in mind, however, that CO 2 is not an electrolyte, because CO 2 itself does not dissociate into ions. Only compounds that dissociate into their component ions in solution qualify as 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 as strong 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 a weak 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. 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 C 6 H 12 O 6.
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. Water, which not only dissolves many compounds but also dissolves more substances than any other liquid, is considered the universal solvent.
A polar molecule with partially-positive and negative charges, it readily dissolves ions and polar molecules. Water is therefore referred to as a solvent: a substance capable of dissolving other polar molecules and ionic compounds. The charges associated with these molecules form hydrogen bonds with water, surrounding the particle with water molecules. This is referred to as a sphere of hydration, or a hydration shell, and serves to keep the particles separated or dispersed in the water.
When ionic compounds are added to water, individual ions interact with the polar regions of the water molecules during the dissociation process, disrupting their ionic bonds.
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