* Electrolytes are substances that conduct electricity when dissolved in water. This happens because they dissociate into ions.

* NaCl (sodium chloride) is an ionic compound. When dissolved in water, it breaks apart into positively charged sodium ions (Na+) and negatively charged chloride ions (Cl-).

* The presence of these free ions allows the solution to conduct electricity.

Therefore, a 1 M solution of NaCl is a strong electrolyte because it completely dissociates into ions in water.