The conductivity of an acid solution is generally related to its concentration of ions. A lower pH indicates a higher concentration of hydrogen ions (H⁺), and thus a more conductive solution.
Given the pH values:
- HA: pH 5.6
- HB: pH 3.9
- HC: pH 4.7
From the pH, we can infer the following:
- HA (pH 5.6) has the highest pH, which means it has the least concentration of H⁺ ions and is the least conductive.
- HC (pH 4.7) is more conductive than HA but less than HB.
- HB (pH 3.9) has the lowest pH, indicating it has the highest concentration of H⁺ ions and is the most conductive.
Thus, the order from least conductive to most conductive is HA < HC < HB.
The correct answer is: HA, HC, HB.