Chlorine + Iron
ObservationThe iron wool burns vogorously with bright flame, forming a brown solid after reaction.
- Chlorine react with iron to form brown iron(III) chloride.
- The reaction of potassium with concentrated hydrochloric acid produces chlorine gas.
2KMnO4 + 16HCl → 2KCl + 2MnCl2 + 5Cl2 + 8H2O
Bromine + Iron
3Br2 + 2Fe → 2FeBr3
ObservationThe iron wool glows brightly but less vigorously. A brown solid is formed.
DiscussionBromine react with iron to form brown iron(III) bromide.
Iodine + Iron
3I2 + 2Fe → 2FeI3
ObservationThe iron wool glows slowly with dim light. A brown solid is formed after reaction.
DiscussionIodine react with iron to form brown iron(III) iodide.
- Halogen is a reactive non-metal. It form salt when react with metal.
- The reactivity decreases down the group.
- Chlorine gas is a poisonous. Excess chlorine gas is absorbed by the soda lime (sodium hydroxide) so that it does not escape to the surrounding.
- Iron wool rather than iron piece is used to increase the rate of reaction.