Redox Colour changes

Cu

Cu2+

SO2

SO4 2-

Mn 2+

H+/MnO4 -

H2O2

O2

H2O

Cr 3+

Cr2O7 2-

Fe 2+

Fe 3+

Cl -

Cl2

Br -

Br2

H2

H +

MnO2

H2O/MnO4 -

MnO4 2-

OH-/MnO4-

I -

I2 (in I - = I3 -)

IO3 -

H2S

S

Pb 2+

PbO2

NO2

NO3 -

C2O4 2-

CO2

S2O3 2-

S4O6 2-

Br2

BrO3 -

Turns blue/black
with starch solution

Forms a white precipitate
with acidified barium chloride solution

Forms a blood-red solution
with potassium thiocynate solution

Turns damp starch-iodide paper
blue/black