Question

Sodium chloride has a crystalline structure made up of $N{a}^{+}$ and $C{l}^{-}$ ions. Why does $NaCl$ not conduct electricity in solid state?

• A. Solids do not conduct electricity.
• B. The ions of $NaCl$ become mobile only in molten state and are not free to move in the solid state.
• C. The crystalline structure does not have ions.
• D. When a bond is formed between Ions they lose their charges.

Answer 1

The correct option is B The ions of $NaCl$ become mobile only in molten state and are not free to move in the solid state.

Properties of a crystalline solid:-

1. These solids have a particular three-dimensional geometrical structure

2. The strength of all the bonds between different ions, molecules, and atoms is equal

3. These solids are the most stable solids as compared to other solids

4. The arrangement order of the ions in crystalline solids is of long order.

These are the reasons that in the solid structure $NaCl$ does not conduct electricity.

In water, crystalline solid compounds conduct electricity due to hydrolysis that occurs due to protonium and hydroxide ions, these ions are able to break the electrostatic attraction between $Na$ and $Cl$, Now the ions are free to move in solution and conduct electricity when needed.

So the correct option is [B]