Halogen displacement reactions [Higher tier only]
The reactivity of the An element placed in Group 7 of the periodic table, which starts with fluorine and ends with astatine. The name 鈥榟alogen鈥 means 鈥榮alt-producing鈥 because halogens produce a range of salts when they react with metals. 鈥 the Group 7 A substance made of one type of atom only. 鈥 decreases as you move down the group. This can be shown by looking at displacement reactions.
Example
When chlorine (as a gas or dissolved in water) is added to sodium bromide solution, the chlorine takes the place of the bromine. Because chlorine is more reactive than bromine, it displaces bromine from sodium bromide.
The solution turns brown. This brown colour is the displaced bromine. The chlorine has gone to form sodium chloride.
In this equation, the Cl and Br have swapped places:
- chlorine + sodium bromide 鈫 sodium chloride + bromine
- Cl2(aq) + 2NaBr(aq) 鈫 2NaCl(aq) + Br2(aq)
This type of reaction happens with all the halogens.