Which of the following actions would most effectively increase the electrical conductivity of an aqueous solution?

• A. Dilute the solution with distilled water.
• B. Decrease the temperature of the solution.
• C. Add more NaCl to the solution.
• D. Add a non-electrolyte such as sugar.

Answer: (C)

Verified step by step guidance

1. Understand that electrical conductivity in an aqueous solution depends on the presence and concentration of ions, which carry electric charge through the solution.
2. Recognize that adding more NaCl (an ionic compound) increases the number of free ions (Na⁺ and Cl⁻) in the solution, thereby increasing its conductivity.
3. Consider that diluting the solution with distilled water decreases the ion concentration, which lowers conductivity because there are fewer charge carriers per unit volume.
4. Note that decreasing the temperature generally reduces ion mobility, which can decrease conductivity, even if ion concentration remains constant.
5. Understand that adding a non-electrolyte like sugar does not produce ions in solution, so it does not increase conductivity; it may even decrease it by diluting the ionic species.