As a chemistry expert, I am well-versed in the principles of how substances interact with their environment, particularly when it comes to the conductivity of salts. Let's delve into the fascinating world of ionic compounds and their behavior in different states of matter.

Salt, in its most common form, is an ionic compound composed of positively charged ions (cations) and negatively charged ions (anions). The reason that salt does not conduct electricity in its solid state is due to the way these ions are arranged within the crystal lattice structure. In the solid state, the ions are held in fixed positions by strong electrostatic forces, known as ionic bonds. These bonds result from the attraction between the oppositely charged ions. Because the ions are immobile in this rigid structure, they cannot move freely to carry an electric current.

However, when salt is dissolved in water, a remarkable transformation occurs. Water is a polar solvent, meaning it has a slight positive charge on one end (the hydrogen atoms) and a slight negative charge on the other end (the oxygen atom). This polarity allows water molecules to interact with the ions in the salt through a process known as solvation. The positively charged hydrogen atoms of water are attracted to the negatively charged ions (anions) of the salt, while the negatively charged oxygen atoms of water are attracted to the positively charged ions (cations). This interaction effectively separates the ions from each other, breaking the ionic bonds and allowing them to move freely within the solution.

The movement of these free ions is what enables the solution to conduct electricity. When an electric field is applied, the negatively charged ions (anions) move towards the positive electrode (cathode), and the positively charged ions (cations) move towards the negative electrode (anode). This directed movement of charge constitutes an electric current, making the solution conductive.

It's also worth noting that the conductivity of a salt solution is not solely dependent on the presence of ions but also on their concentration. The more ions present in the solution, the higher the conductivity, assuming that the ions are free to move and not precipitating out or forming other compounds that might hinder their movement.

In summary, the conductivity of salt in water is a result of the polar nature of water molecules that solvate and separate the ions, allowing them to move freely and carry an electric current. This process is not possible in the solid state due to the rigid lattice structure that holds the ions in place.

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Conductive when liquid - ions are charged particles, but ionic compounds can only conduct electricity if their ions are free to move. So ionic compounds do not conduct electricity when they are solid, but they do conduct electricity when they are dissolved in water or when they are melted.read more >>