Example 1:   2Na  +  S  ® Na₂S
                          Na° ® Na⁺¹  (oxidized)
                           S° ® S^-2     (reduced)
     Oxidation:   2Na ® 2Na⁺¹ + 2e^-1
     Reduction:   S + 2e^-1 ® S^-2
     Overall:      2Na  +  S ®2Na⁺¹ +  S^-2
     Overall equation is sum of oxidation/reduction equations (electrons always cancel).

     Example 2:   2Al_(s) + 3ZnCl_2(aq) ® AlCl_3(aq) + 3Zn_(s)
     Here is a single substitution with Al replacing Zn:
                          Al°® Al⁺³   (oxidized)
                          Zn⁺² ® Zn°  (reduced)
                          Cl^-1 ® Cl^-1   (spectator ion)
     Oxidation:   2Al ® 2Al⁺³ +  6e^-1
     Reduction:  3Zn⁺² + 6e^-1 ® 3Zn
     Overall:      2Al  + 3Zn⁺² ®2Al⁺³ + 3Zn

     Next we look at REDOX reactions taking place in water under acidic or basic conditons.
     For acidic conditions, balance with H⁺¹, H₂O, or H⁺¹/H₂O
     For basic conditions, balance with OH^-1, H₂O, or OH^-1/H₂O
     Oxidation & reduction always go together but we begin with half reactions:

     Example 3:   AsH₃ ® As  (acidic)
                          As^-3  ® As°    (oxidized)
                         AsH₃® As + 3H⁺¹ + 3e^-1  (oxidation)

    Example 4:  VO₃^-1® V⁺²   (acidic)
                              V⁺⁵® V⁺²     (reduced)
                       VO₃^-1® V⁺²+ 3H₂O
                      VO₃^-1+ 6H⁺¹ + 3e^-1 ® V⁺² + 3H₂O(reduction)

     Example 5:   U⁺⁴® UO₂⁺¹   (acidic)
                          U⁺⁴+2H₂O ® UO₂⁺¹
                        U⁺⁴+ 2H₂O ® UO₂⁺¹  +  4H⁺¹ + 1e^-1  (oxidation)

     Example 6:  MnO₄^-1® Mn⁺²    (acidic)
                          MnO₄^-1  ® Mn⁺²+ 4H₂O
                        MnO₄^-1+  8H⁺¹ +  5e^-1® Mn⁺² + 4H₂O  (reduction)

     But oxidation always accompanies reduction reaction. We now look at full (overall) reactions.

     Example 7:   MnO₄^-1+  Br^-1 ® Mn⁺²  + Br₂     (acidic)
                                 Mn⁺⁷® Mn⁺²  (reduced)
                            Br^-1 ® Br°     (oxidized)
      Oxidation:       2Br^-1®  Br₂+  2e^-1
      Reduction:    MnO₄^-1+  8H⁺¹ +  5e^-1® Mn⁺²+ 4H₂O
     Multiply oxidation by 5 and reduction by 2 (e^-1 lost must equal e^-1 gained):
     [2Br^-1 ®  Br₂+  2e^-1] 5
     [MnO₄^-1+  8H⁺¹ + 5e^-1® Mn⁺²+ 4H₂O]2
     Oxidation:    10Br^-1®  5Br₂+  10e^-1
     Reduction:  2MnO₄^-1+  16H⁺¹ +  10e^-1® 2Mn⁺² + 8H₂O
     Overall:       2MnO₄^-1+ 16H⁺¹ + 10Br^-1® 2Mn⁺² +  5Br₂  + 8H₂O

     Example 8:   Co  + NO₃^-1® Co⁺³  + NO₂     (acidic)
                              Co° ® Co⁺³   (oxidized)
                          N⁺⁵ ® N⁺⁴   (reduced)
     Oxidation:   Co® Co⁺³  +  3e^-1
     Reduction:   [NO₃^-1+ 2H⁺¹ + 1e^-1® NO₂ +  H₂O] 3
     Overall:      Co+ 3NO₃^-1+ 6H⁺¹® Co⁺³ + 3NO₂ +  3H₂O

   For REDOX under basic conditions, use OH^-1/H₂O to balance or first balance under acidic conditions
   followed by complete neutralization of H⁺¹ with OH^-1.

     Example 9:   MnO₄^-1® MnO₂   (basic)
                          Mn⁺⁷ ® Mn⁺⁴  (reduced)
                         MnO₄^-1  + 4H⁺¹ + 3e^-1® MnO₂+  2H₂O         (4H⁺¹ + 4OH^-1 ® 4H₂O)
                                             +4OH^-1                          +4OH^-1
                                     MnO₄^-1+ 4H₂O + 3e^-1 ® MnO₂+ 4OH^-1+ 2H₂O (subtract 2H₂O from each side)
                        MnO₄^-1+ 2H₂O + 3e^-1 ® MnO₂+ 4OH^-1

     Example 10:   ClO^-1® Cl^-1  (basic)
                           Cl⁺¹ ® Cl^-1    (reduced)
                         ClO^-1 + 2H⁺¹ + 2e^-1®Cl^-1+ H₂O
                                   +2OH^-1                     +2OH^-1
                         ClO^-1 + H₂O + 2e^-1® Cl^-1 + 2OH^-1

     Example 11:   Br₂® 2BrO₃^-1  (basic)
                           Br° ® Br⁺⁵     (oxidized)
                           Br₂ +  6H₂O ® 2BrO₃^-1 + 12H⁺¹ + 10e^-1
                                 +12OH^-1                  +12OH^-1
                         Br₂ +12OH^-1  ® 2BrO₃^-1  + 6H₂O + 10e^-1

     Example 12:   Sn ® Sn(OH)₄^-2   (basic)
                         Sn  + 4OH^-1® Sn(OH)₄^-2 + 2e^-1  (reduced)

     Example 13:   Al  +  S  ® HS^-1 + Al(OH)₃      (basic)
                           Al° ® Al⁺³   (oxidized)
                            S° ® S^-2   (reduced)
     Oxidation:     [Al + 3OH^-1® Al(OH)₃+ 3e^-1]2
     Reduction:     S + H⁺¹ + 2e^-1® HS^-1
                             +OH^-1             +OH^-1
                            [S + H₂O + 2e^-1 ® HS^-1  + OH^-1]3
     Overall:       2Al  +  3S + 3H₂O + 3OH^-1 ® 3HS^-1 + 2Al(OH)₃

     Example 14:   NO₂^-1  + Al  ® NH₃ + Al(OH)₄^-1    (basic)
                            Al° ® Al⁺³   (oxidized)
                            N⁺³ ® N^-3   (reduced)
     Oxidation:     [Al + 4OH^-1® Al(OH)₄^-1 + 3e^-1]2
     Reduction:  NO₂^-1 + 7H⁺¹ + 6e^-1 ® NH₃+  2H₂O
                                +7OH^-1                     +7OH^-1
                    [NO₂^-1 + 5H₂O  + 6e^-1 ® NH₃+  7OH^-1]
     Overall:     2Al + NO₂^-1 + 5H₂O  + OH^-1® 2Al(OH)₄^-1 + NH₃