How do halogens (Cl2, Br2, I2) react with halides (Cl-, Br-, I-)?

Can we explain this reactivity?

1 answer

F2 is a halogen, too. Halogens replace the ions below it; e.g.,
F2 + 2Cl^- ==> Cl2 + 2F^-
F2 + 2Br^- ==> Br2 + 2F^-
etc
Cl2 + 2Br^- ==> 2Cl^- + Br2
Cl2 + 2I^- ==> 2Cl^- + I2

Br2 + 2I^- --> 2Br^- + I2