Reactions of halogens

IGCSE Chemistry 

Reactions of halogens   

 

Introduction

The Group 7 elements are called the halogens. This experiment involves some reactions of the halogens.

What to record

Complete the table by recording any colour changes or not.  Indicate the colours.

	Effect on indicator paper	Reaction with potassium chloride solution	Reaction with potassium bromide solution	Reaction with potassium iodide solution
Chlorine water
Bromine water
Iodine water

 

What to do

1.     Put a piece of Universal Indicator paper onto a white tile.

2.     Use a glass stirring rod to transfer a few drops of the first solution onto the indicator paper.

3.     Repeat this with a fresh piece of paper and the different solutions.

4.     In a test-tube, add some chlorine solution to a solution of potassium bromide.

5.     Add some chlorine solution to a solution of potassium iodide.

6.     Now try mixing solutions of bromine and potassium iodide. If there is time, mix the other combinations of solutions to complete the table.

Safety

Wear eye protection. Do not breathe chlorine gas.

 

Questions

1.     Which halogen solution is the strongest bleaching agent?

2.     Which halogen is the most reactive?

3.     Write a word and symbol equation for the reaction of chlorine with potassium bromide.