This is a pretty basic question, and I know it has something to do with conductivity, but I'm not quite sure how they are related.

  • $\begingroup$ Blake, please see my edits -- if you're unhappy with anything I changed, please feel free to change it back, or roll back my edit entirely. $\endgroup$ – hBy2Py Jan 30 '17 at 21:37

The reasoning here is two-fold. The solubility of most electrolytes increases with temperature, and water's ionization constant also increases with temperature. On the whole this means more ions, and thereby better conductivity.

  • $\begingroup$ Can you clarify on the ionization constant because I thought it decreased when temperature increased. $\endgroup$ – jkd Jan 31 '17 at 1:49
  • $\begingroup$ @jakekimds The value of $\mathrm{p}K_\mathrm{a}$ does decrease with increasing temperature, yes. But, this means that the proper ionization constant, $K_\mathrm{a}$, increases with increasing temperature. $\endgroup$ – hBy2Py Jan 31 '17 at 3:58

ringo makes good points in his answer. Additionally, though, the increased temperature enhances mass transfer of ions to/from the electrode surfaces by at least two mechanisms:

  1. Higher temperature results in lower electrolyte viscosity, leading to a thinner fluid dynamic boundary layer and concomitant greater mass transfer to/from the electrode surfaces.

  2. Higher temperature also increases the diffusivities of the electrolyte solutes, which also contributes to increased mass transfer to/from the electrodes.

  • $\begingroup$ very good additional points. $\endgroup$ – MaxW Jan 30 '17 at 21:04

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.