-1
$\begingroup$

In this article. Authors use $\ce{KI}$ in potentiometric titration of ascorbic acid with permanganate and dont describe why! Anyvody know why should we use $\ce{KI}$ in potentiometric titration of ascorbic acid with permanganate?

$\endgroup$
2
$\begingroup$

Potassium iodide is used as an indicator. While there is ascorbic acid in solution, $\ce{KI}$ is protected from being oxidized by potassium permanganate. However, the moment ascorbic acid runs out, potassium iodide gets oxidized to iodine, $\ce{I2}$. This gives the solution a brownish color (blue if you add starch, which will also make it easier to see).

$\endgroup$

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.