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The preparation of salt solutions often takes place in unsealed beakers. In this case the conductivity of purified water often is 10 to 20 times higher. A discussion can be found below. Typical drinking water is in the range of 200–800 μS/cm, while sea water is about 50 mS/cm [3] (or 0.05 S/cm).
An electrolyte is a substance that conducts electricity through the movement of ions, but not through the movement of electrons. [1] [2] [3] This includes most soluble salts, acids, and bases, dissolved in a polar solvent like water.
Electrical conductivity of water samples is used as an indicator of how salt-free, ion-free, or impurity-free the sample is; the purer the water, the lower the conductivity (the higher the resistivity). Conductivity measurements in water are often reported as specific conductance, relative to the conductivity of pure water at 25 °C.
Liquids made of compounds with only covalent bonds cannot conduct electricity. Certain organic ionic liquids, by contrast, can conduct an electric current. While pure water is not an electrical conductor, even a small portion of ionic impurities, such as salt, can rapidly transform it into a conductor.
Strong electrolytes conduct electricity only in aqueous solutions, or in molten salt, and ionic liquid. Strong electrolytes break apart into ions completely. The strength of an electrolyte does not affect the open circuit voltage produced by a galvanic cell. But when electric current flows, stronger electrolytes result in smaller voltage losses ...
When the salts are dissolved in a liquid or are melted into a liquid, they can conduct electricity because the ions become completely mobile. For this reason, molten salts and solutions containing dissolved salts (e.g., sodium chloride in water) can be used as electrolytes. [75]
If water has even a tiny amount of such an impurity, then the ions can carry charges back and forth, allowing the water to conduct electricity far more readily. It is known that the theoretical maximum electrical resistivity for water is approximately 18.2 MΩ·cm (182 kΩ ·m) at 25 °C. [ 56 ]
At 20 °C (68 °F) one liter of water can dissolve about 357 grams of salt, a concentration of 26.3 percent by weight (% w/w). At 100 °C (212 °F) (the boiling temperature of pure water), the amount of salt that can be dissolved in one liter of water increases to about 391 grams, a concentration of 28.1% w/w.