We are always told and taught that water conducts electricity. And, Water + Electricity is such a dangerous combination, that it can cause electric shocks for those who come into contact with it.
But the fact is water is a bad conductor of electricity, i.e. it is a good insulator. If you really think about it and delve into the depths of chemistry on this issue, you can see that pure water is actually not a good conductor of electricity, that is, it does not allow electricity to flow through it.
What is Pure Water in Chemistry
Water from the sources such as sea, river, streams, lakes, etc. is a mixture of many different substances. Some of these substances can be observed when the water evaporates and leaves behind the substances. Water, H2O, is a pure substance, a compound made of hydrogen and oxygen.
Although water is the most abundant substance on earth, it is rarely found naturally in its pure form. Most of the time, pure water has to be created. Pure water is called distilled water or deionized water. In distilled water all of the dissolved substances mixed in water have been removed by evaporation. As water evaporates, it distills, or leaves the salt behind. The pure evaporated water is collected and condensed to form distilled water.
Pure Water Doesn’t Conduct Electricity
In order for electricity to flow through a liquid, a movement of charge must take place through the liquid. Fully deionized water, in other words, absolutely “pure” water has no ions. Consequently, no charge flows through water, so pure water does not conduct electricity. In distilled water, there are no impurities and thus no ions. There are only neutral molecules, and these neutral molecules lack a charge. For this reason, distilled water is also unable to conduct electricity.
Water stops being an excellent insulator once it starts dissolving substances around it. Salts, such as common table salt (sodium chloride (NaCl)) is the one we know best. In chemical terms, salts are ionic compounds composed of cations (positively charged ions) and anions (negatively charged ions). When water contains these ions it will conduct electricity, such as from a lightning bolt or a wire from the wall socket, as the electricity from the source will seek out oppositely-charged ions in the water. Too bad if there is a human body in the way.
“Interestingly, if the water contains very large amounts of solutes and ions, then the water becomes such an efficient conductor of electricity that an electrical current may essentially ignore a human body in the water and stick to the better pathway to conduct itself—the masses of ions in the water. That is why the danger of electrocution in sea water is less than it would be in tap water.”
Is Tap Water a Pure Water
Tap water is not distilled. Most public tap water has chlorine. Chlorine is used to kill microbes in the water. Public tap water may also have other minerals intentionally dissolved in it, like fluoride, which prevents tooth decay. In some areas, tap water comes directly from wells and is untreated. The mineral composition of well water varies from place to place and gives water from different areas their distinctive tastes.
- Pure water is a bad conductor of electricity because it is feebly ionized.
- For a substance to be a good conductor of electricity, there should be free electrons to transfer current.
- Impurities present in water get ionized to conduct electricity.