Page 23 - Curriculum Visions Dynamic Book

Salt as an electrolyte
To demonstrate how salt behaves as an electrolyte, salt is placed in water and a battery is connected to a circuit like that shown here.
Because the salt water conducts electricity, the bulb will light. This happens because the sodium
and chlorine ions are free to move. When a voltage is applied, the negative ions flow towards the positive side of the battery, and the positive ions move towards the negative side of the battery. If the ions were not free to move, they could not complete the circuit in this way. Pure water, for example, is a poor electrical conductor and solid sodium chloride will not conduct electricity at all.
bond: chemical bonding is either a transfer or sharing of electrons by two or more atoms.
electrolysis: an electrical–chemical process that uses an electric current to cause the break up of a compound and the movement of metal ions in a solution. The process happens in many natural situations (as for example in rusting) and is also commonly used in industry for purifying (refining) metals or for plating metal objects with a fine, even metal coating.
electrolyte: a solution that conducts electricity.
ion: an atom, or group of atoms, that has gained or lost one or more electrons and so developed an electrical charge.
solution: a mixture of a liquid and at least one other substance (e.g. salt water). Mixtures can be separated out by physical means, for example by evaporation and cooling.
Also...
Molten salt conducts electricity.
If salt is heated until it melts and
an electric current flows through it, then the sodium ions will move to the cathode (where solid sodium metal will accumulate) while chloride ions will move to the anode where they are given off as gas. This process can be used in industry to produce both chlorine gas and sodium metal.
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When copper electrodes connected to a battery are immersed in a salt solution, a current will flow. Thus metal will leave the anode of the cell and migrate through the water to be redeposited on the cathode.
You can see this effect if the cell is left running for some time. The colour of the solution begins to change, showing that copper has been dissolved from the anode and transferred to the water. The copper anode also becomes brighter as the metal is lost from the surface.
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