A student designs an experiment to test the conductivity of distilled water and salt water. The experimental set-up and results are shown below.

Question

Which of the following BEST explains why salt water helped conduct electricity?

Answer 1

The salt water helped conduct electricity better than distilled water because salt (sodium chloride) dissociates into ions when dissolved in water, creating positive sodium ions (Na+) and negative chloride ions (Cl-). These free ions are able to move in the solution and carry electric charge, therefore allowing the salt water to conduct electricity. Distilled water, on the other hand, does not contain any free ions and is therefore a poor conductor of electricity.