Electrical conductivity measurements are most affected by which factor?

Electrical conductivity is a measure of a solution's ability to conduct electric current, which is primarily influenced by the concentration and mobility of ions in the water. Temperature plays a critical role in this process. As temperature increases, the kinetic energy of ions also increases, leading to greater mobility and higher conductivity. Therefore, temperature changes can significantly affect the conductivity readings.

While the presence of solids can have some influence, it is typically the ions dissolved in water that are primarily responsible for conductivity. Likewise, the pH level can impact the concentration of hydrogen and hydroxide ions, but its effect is often secondary when compared to temperature. The volume of the sample primarily influences dilution but does not fundamentally change the conductivity properties unless the concentration of ions changes with it. Thus, the factor that most directly affects electrical conductivity measurements is temperature changes.