Color change of potassium permanganate during a titration with Fe(II)

Is it possible for potassium permanganate to have color change (in a titration) from colorless to pink? If so, then in what circumstances (particularly for a titration)? I have been always been taught that color change for potassium permanganate is purple/pink to colorless. I have scoured the whole internet searching for an example and I couldn't find one.


The problem is a question in a recent A level paper which asked about the color change of $\ce{KMnO4}$ with an $\ce{Fe^2+}$ solution. The answer was colorless to pink. The examiner report further mentioned that many students wrote purple/pink to colorless, however it was marked incorrect.


Can someone explain the ambiguity here?




An aqueous solution of potassium permanganate, $\ce{KMnO4}$ is of purple colour, regardless if the solution is neutral, acidic, or basic. Potassium permanganate is a relative powerful oxidizer. (As a look-up in a table of standard electrode potentials may tell.) If one considers acidic conditions $\ce{KMnO4}$ may *oxidize* material, like


$$\ce{Fe^{2+} -> Fe^{3+} + e-}$$


while being reduced from oxidation state +7 to oxidation state +2 in the form of $\ce{Mn^{2+}}$. Aqueous solutions of, say $\ce{MnSO4}$, however are almost colourless. On the other hand, $\ce{Fe^{2+}}$ alone is not a strong oxidizer, under normal conditions incapable to generate permanganate. That is why this analysis is widely used ([application note](http://www.metrohm.ru/Special/Thermometric/1353160_AN-h128.pdf), [example 1](http://www.lahc.edu/classes/chemistry/arias/exp%208%20-%20redox.pdf), [example 2](http://www.austincc.edu/dsackett/CHEM1412/lab/1412exp28.pdf) in lab classes and beyond).


The *end point* of the redox titration is reached if all $\ce{Fe^{2+}}$ is oxidized, so that under addition of additional $\ce{KMnO4}$, your analyte solution remains purple.


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