\[Mn{{O}_{4}}\]is a good oxidising agent in different medium changing to \[MnO_{4}^{-}\xrightarrow[{}]{{}}M{{n}^{2+}}\] \[\xrightarrow[{}]{{}}MnO_{4}^{2-}\] \[\xrightarrow[{}]{{}}Mn{{O}_{2}}\] \[\xrightarrow[{}]{{}}M{{n}_{2}}{{O}_{3}}\] Changes in oxidation number respectively are: