Why is no current flow possible in pure water?

When does a material conduct electricity?

In order to enable an electrical current to flow in a material, regardless of whether it is a solid, liquid or gas, you need free and mobile charge carriers in this material.

• In a metal, these charge carriers are known electrons, which are easily separated from the atoms and ensure the flow of current. Electrons are responsible for the good conductivity of the metals.
• In semiconductors, electrons, and in some cases holes (the remaining positive gaps), also provide conductivity. However, as the term "semiconductor" already suggests, their conductivity is lower.
• Isolators or Non-conductors such as glass and many special ceramics have no or only a very small amount of charge carriers. They therefore do not conduct electricity.
• In many liquids there are no moving electrons, but there are other charged particles that enable the flow of electricity. These are negatively or positively charged ions, i.e. atoms that lack an electron in the shell or that have picked up an additional electron. A good example are salts such as NaCl dissolved in water, which are then converted into positively charged Na
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  ⁺Ions and negatively charged Cl^--Ions split and conduct the electric current.


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• Even gases can become electrically conductive under certain circumstances, namely when, for example, some of the air molecules or atoms are ionized. Fluorescent tubes and flashes are suitable examples here.

Can electricity flow in pure water?

Tap water that can be taken from a tap is, as can easily be shown experimentally, electrically conductive. It contains a small amount of dissolved salts which, as ions, enable the flow of electricity in this liquid.

• In the same experiment, no current flow can be detected in pure water. It should be distilled or distilled under pure water. demineralized water. It simply lacks the ions from the salts or salts that are important for charge transport. Minerals.
• However, more precise measurements show that even pure water has an extremely low conductivity. In no case does this conductivity come close to that of metals; However, pure water is more conductive than most of the non-conductors used as insulation.
• But where does this flow of electricity, albeit a small one, come from with pure water? Even in pure water, which actually only comes from H.₂O molecules should exist, a very small number of the water molecules split into ions (OH^- and H⁺that adapts to an H₂O molecule attaches and an H₃O⁺Ion forms). This fact is in the chemistry as Autoprotolysis designated. These few ions lead to low conductivity even in pure water. Incidentally, the two types of ions are called oxonium and hydroxide ions.

In pure water, a very low current flow is definitely possible, but this can only be detected with precise measuring devices.