Error:
S2O8%3A2- %2B Mn%3A2%2B %2B OH%3A- %3D MnO2 %2B SO4%3A2- %2B H2O
^
Unexpected character ('%')S2O8%3A2- %2B Mn%3A2%2B %2B OH%3A- %3D MnO2 %2B SO4%3A2- %2B H2O
^
Unexpected character ('%')