21. Solving a chemistry problem

84. Complete the equations of redox reactions.
2. Indicate the oxidizing agent and reducing agent, the direction of electron transfer.
3. Write down the values of the normal redox potentials of the corresponding pairs
4. For what purposes can these reactions be used in qualitative analysis?
5. Solve the first two equations using the electron-ion balance method, the rest - using the electron balance method.

84.
CoS H2O2 HCl
Cr(NO3)2 Br2 NaOH
Mn(NO3)2 PbO2 HNO3
NaI NaNO2 H2SO4
Cu Hg(NO3)2