What happens when purple permanganate solution is reduced in a titration?

When purple permanganate solution undergoes reduction in a titration, it turns colorless. This occurs because permanganate ions (MnO4-) are reduced to manganese (II) ions (Mn2+), which are colorless in solution. The distinct violet color of the permanganate is a result of its high oxidation state. The decolorization indicates that the reaction is progressing, allowing the analyst to see when the endpoint of the titration is reached. This property of permanganate makes it a popular choice as a titrant in redox titrations, as the visible color change provides clear evidence of the reaction's completion.

In contrast, the other options do not accurately describe the behavior of permanganate during reduction. It does not become bluer, turn green, or darken further; these options are not aligned with the known chemical behavior of permanganate ions in a reduction reaction.