Which of the following is an example of an electrolyte?

An electrolyte is a substance that dissociates into ions when dissolved in a solvent, usually water, and thus is capable of conducting electricity. Sodium chloride, commonly known as table salt, is a prime example of an electrolyte because when it is dissolved in water, it separates into sodium ions (Na+) and chloride ions (Cl-). These free-moving ions in solution allow for the conduction of electrical current.

In contrast, the other options do not exhibit the properties of an electrolyte. Water, while a solvent for electrolytes, is not an electrolyte itself because it does not produce ions in significant quantities. Sugar, when dissolved, does not dissociate into ions but rather remains as intact molecules, making it a non-electrolyte. Oil is a non-polar substance and does not dissolve in water or dissociate into ions, thus it also does not function as an electrolyte. Therefore, sodium chloride is the correct choice as it directly demonstrates the characteristics of an electrolyte by forming ions in solution.