NCEA Level 3 Chemistry – Aqueous Chemistry (AS91393) Practice Exam

Conductivity in solutions is primarily determined by the presence and concentration of ions. When ionic compounds dissolve in water, they dissociate into positively and negatively charged ions. The greater the concentration of these ions in the solution, the more charge carriers there are available to facilitate the flow of electric current. Thus, higher ion concentration improves conductivity.

In contrast, dilute solutions, which have fewer ions, have lower conductivity because there are not enough charge carriers to effectively conduct electricity. Strong and weak acids or bases can both contribute to conductivity depending on how completely they dissociate in solution, but it is the concentration of all ions present that explicitly influences conductivity.

Neutral solutions, like pure water, contain very few ions (mostly from the dissociation of water itself), which means they are not good conductors. Therefore, the true statement regarding conductivity in solutions is the one that asserts a direct relationship between higher ion concentration and improved conductivity.