1
Q
reduction
A
gain of electrons
-decrease in oxidation number
2
Q
oxidation
A
loss of electrons
-increase in oxidation number
3
Q
chromium half equation
A
Cr2O7 2- + 14H+ 6e –> 2Cr 3+ + 7H2O
4
Q
manganese half equation
A
MnO4 + 8H+ + 5e –> Mn 2+ +4H2O
5
Q
hydrogen peroxide half equation
A
H2O2 –>O2 + 2H+ +2e
6
Q
iron half equation
A
Fe2+ –> Fe3+ + e
7
Q
iodine thiosulphate equation
A
2S2O3 2- + I2 –> 2I + S4O6 2-
8
Q
iodinethiosulphate reaction
A
starch s added making solution blue black then once all iodine is reduced to I- solution goes colourless
-end result
