Redox

Mnemonic

• 失升氧化还原剂，得降还原氧化剂

• Primary cell and Electrolytic cell

  • 留点铁修路 \( S^{2-} > I^{-} > Fe^{2+} > Br^{-} > Cl^{-} > OH^{-} \) -> \( S - I_2 - Fe^{3+} - Br_2 - Cl_2 - O_2 \)
  • 印铁通勤 \( Ag^{+} > Fe^{3+} > Cu^{2+} > H^{+} \) -> \( Ag - Fe^{2+} - Cu - H_2 \)

Procedure: 0

When the chemical valences of elements of a substance is difficult to know, they can be marked with 0.