Halogens React with Metals

 Chlorine + Iron

3Cl2 + 2Fe → 2FeCl3

Observation

The iron wool burns vogorously with bright flame, forming a brown solid after reaction.

Discussion

  1. Chlorine react with iron to form brown iron(III) chloride.
  2. The reaction of potassium with concentrated hydrochloric acid produces chlorine gas.
2KMnO4 + 16HCl → 2KCl + 2MnCl2 + 5Cl2 + 8H2O

Bromine + Iron


3Br2 + 2Fe → 2FeBr3

Observation

The iron wool glows brightly but less vigorously. A brown solid is formed.

Discussion

Bromine react with iron to form brown iron(III) bromide.

Iodine + Iron


3I2 + 2Fe → 2FeI3

Observation

The iron wool glows slowly with dim light. A brown solid is formed after reaction.

Discussion

Iodine react with iron to form brown iron(III) iodide.

Note:

  1. Halogen is a reactive non-metal. It form salt when react with metal.
  2. The reactivity decreases down the group.
  3. 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.
  4. Iron wool rather than iron piece is used to increase the rate of reaction.


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