Error:
KCr2O7 %2B HBr %3D CrBr %2B Br2 %2B KBr %2B H2O
^
Unexpected character ('%')KCr2O7 %2B HBr %3D CrBr %2B Br2 %2B KBr %2B H2O
^
Unexpected character ('%')