Răspuns:
3 Hg + 8 HNO3 → 3 Hg(NO3)2 + 2 NO + 4 H2O
2 NV + 6 e- → 2 NII (reducere)
3 Hg0 - 6 e- → 3 HgII (oxidare)
HNO3 agent oxidant
Hg agent reducator.
C + 2 H2SO4 → 2 SO2 + CO2 + 2 H2O
C0 - 4 e- → CIV (oxidare)
2 SVI + 4 e- → 2 SIV (reducere)
C agent reducator
H2SO4 agent oxidant
S +2 H2SO4 → 3 SO2 + 2 H2O
S0 - 4 e- → SIV (oxidare)
2 SVI + 4 e- → 2 SIV (reducere)
S agent readucator
H2SO4 agent oxidant
Explicație: