Why is an ionic solid non-conductive, but conductive in aqueous solution?

1 Answer
Dec 4, 2016

Answer:

Because the ions that constitute ionic compounds are not free to move in the solid state...........

Explanation:

The generic ionic solid is #MX#, and consists of equal number of #M^+# and #X^-# ions that are held together in a non-molecular, electrostatically bound lattice. The ions are not free to move in the solid state, and thus cannot carry a charge.

In certain circumstances, with certain solvents, for instance water, the ionic solid can dissolve to produce #M^(+)(aq)# and #X^(-)(aq)# ions that are free to move in solution. We write #M^(+)(aq)# to represent the aquated ion, i.e. #[M(OH_2)_6]^+# or something similar. And in solution these ions can carry a charge in that the ions are mobile.

Water is an excellent solvent for solvating ions. However, it does not solvate all ions, and it is not the only solvent available.