Replacement Reactions of Halogens

Hazards

• Methylene chloride is toxic.
• Chlorine water and bromine water are corrosive and toxic.

Chemicals and Solutions

• 0.1M KCl
• 0.1M KBr
• 0.1M KI
• Chlorine water
• Bromine water
• Iodine water
• Methylene chloride

Materials

• Three ringstands
• Six 250 mL separatory funnels with stoppers
• Six rings

Procedure

Perform the following reactions in the separatory funnels, and extract each reaction mixture with methylene chloride in order to see the characteristic color of the halogen.

$\mathrm{Cl}{\phantom{A}}_2{\phantom{A}}_{(\mathrm{g})}+2\mathrm{Br}{\phantom{A}}^{-}{\phantom{A}}_{(\mathrm{aq})}⟶\mathrm{Br}{\phantom{A}}_2{\phantom{A}}_{(\mathrm{g})}+2\mathrm{Cl}{\phantom{A}}^{-}$

$\mathrm{Cl}{\phantom{A}}_2{\phantom{A}}_{(\mathrm{g})}+2\mathrm{I}{\phantom{A}}^{-}{\phantom{A}}_{(\mathrm{aq})}⟶\mathrm{I}{\phantom{A}}_2{\phantom{A}}_{(\mathrm{g})}+2\mathrm{Cl}{\phantom{A}}^{-}$

$\mathrm{Br}{\phantom{A}}_2{\phantom{A}}_{(\mathrm{g})}+2\mathrm{I}{\phantom{A}}^{-}{\phantom{A}}_{(\mathrm{aq})}⟶\mathrm{I}{\phantom{A}}_2{\phantom{A}}_{(\mathrm{g})}+2\mathrm{Br}{\phantom{A}}^{-}$

$\mathrm{Br}{\phantom{A}}_2{\phantom{A}}_{(\mathrm{g})}+2\mathrm{Cl}{\phantom{A}}^{-}{\phantom{A}}_{(\mathrm{aq})}⟶\mathrm{no}\mathrm{reaction}$

$\mathrm{I}{\phantom{A}}_2{\phantom{A}}_{(\mathrm{g})}+2\mathrm{Br}{\phantom{A}}^{-}{\phantom{A}}_{(\mathrm{aq})}⟶\mathrm{no}\mathrm{reaction}$

$\mathrm{I}{\phantom{A}}_2{\phantom{A}}_{(\mathrm{g})}+2\mathrm{Cl}{\phantom{A}}^{-}{\phantom{A}}_{(\mathrm{aq})}⟶\mathrm{no}\mathrm{reaction}$