The following aqueous solutions were tested with a light bulb conductivity apparatus, as shown in Figure 4.3. What result—dark, dim, or bright—do you expect from each? (a) 0.10 M potassium chloride (b) 0.10 M methanol (c) 0.10 M acetic acid

Electrolytes are substances that dissociate into ions when dissolved in water, allowing the solution to conduct electricity. Strong electrolytes, like potassium chloride, fully dissociate into ions, resulting in high conductivity. Weak electrolytes, such as acetic acid, partially dissociate, leading to lower conductivity. Non-electrolytes, like methanol, do not dissociate into ions and therefore do not conduct electricity.

The conductivity of a solution can be tested using a light bulb apparatus, where the brightness of the bulb indicates the solution's ability to conduct electricity. A bright bulb signifies a strong electrolyte with high ion concentration, while a dim bulb indicates a weak electrolyte, and a dark bulb shows a non-electrolyte. This method visually demonstrates the differences in conductivity among various solutions.

The concentration of a solution, measured in molarity (M), affects its conductivity based on the degree of ionization. A 0.10 M solution of a strong electrolyte like potassium chloride will produce a significant number of ions, enhancing conductivity. In contrast, a 0.10 M solution of a weak electrolyte like acetic acid will yield fewer ions due to partial ionization, resulting in lower conductivity. Non-electrolytes do not contribute ions, leading to no conductivity.