The Half Equations of Dichromate(IV) and Manganate(VII)

Dichromate(IV) and Manganate(VII) are used as oxidising agents.

An oxidising agent being a substance that causes another substance to lose electrons in a chemical reaction. In doing so, the oxidising agent itself is reduced (gains electrons).

Half equation of Dichromate(IV)

Cr₂O₇^2- —> 2Cr³⁺ + 7H₂O

Cr₂O₇^2- + 14H⁺ + 6e^- —> 2Cr³⁺ + 7H₂O

colour change - orange to green

Half equation of Manganate(VII)

Mn⁷⁺ + 5e —> Mn²⁺

MnO₄^- —> Mn²⁺ + 4H₂O

O₄^- + e —> 4O

MnO₄^- + 8H⁺ + 5e —> Mn²⁺ + 4H₂O

colour change - purple to colourless