Practical activity - determining a reactivity series
There are a number of ways that you could determine a A list of elements in order of their reactivity, usually from most reactive to least reactive. in Chemistry. This is an outline of the steps needed for one of these methods.
Aim
To determine the reactivity series of the halogens.
Method
- in three separate test tubes add some potassium chloride, potassium bromide, and potassium iodide
- using a pipette, add some chlorine water to the potassium bromide solution, and potassium iodide solution
- observe and record what happens to the potassium bromide solution, and potassium iodide solution
- repeat step 1
- using a pipette, add some bromine water to the potassium chloride solution and potassium iodide solution
- observe and record what happens to the potassium chloride solution and potassium iodide solution
- repeat step 1
- using a pipette, add some iodine water to the potassium chloride solution and the potassium bromide solution
- observe and record what happens to the potassium chloride solution and potassium bromide solution
Image caption, 1. Chlorine water is added to three solutions
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A halogen cannot displace itself from a solution of one of its salts, eg potassium bromine would not displace bromine water, so these combinations are not done.
Results
Record your observations in a table:
| Potassium chloride solution | Potassium bromide solution | Potassium iodide solution | Number of reactions | |
| Chlorine | Not done | Solution darkens | Solution darkens | 2 |
| Bromine | No visible reaction | Not done | Solution darkens | 1 |
| Iodine | No visible reaction | No visible reaction | Not done | 0 |
| Chlorine | |
|---|---|
| Potassium chloride solution | Not done |
| Potassium bromide solution | Solution darkens |
| Potassium iodide solution | Solution darkens |
| Number of reactions | 2 |
| Bromine | |
|---|---|
| Potassium chloride solution | No visible reaction |
| Potassium bromide solution | Not done |
| Potassium iodide solution | Solution darkens |
| Number of reactions | 1 |
| Iodine | |
|---|---|
| Potassium chloride solution | No visible reaction |
| Potassium bromide solution | No visible reaction |
| Potassium iodide solution | Not done |
| Number of reactions | 0 |
Image caption, 1. The result of adding chlorine to the three solutions
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Analysis
Chlorine could displace bromine and iodine, bromine could only displace iodine, but iodine could not displace chlorine or bromine.
So the order of reactivity is: chlorine > bromine > iodine.
Hazards, risks and precautions
Evaluate the hazards and the precautions needed to reduce the risk of harm. For example:
| Hazard | Possible harm | Possible precaution |
| Chlorine solution | Chlorine gas is produced, which is toxic if inhaled. | Make sure the lab is well ventilated and avoid inhaling the gas. |
| Bromine solution | Toxic bromine vapour is produced. Solution irritates the skin. | Make sure the lab is well ventilated and avoid inhaling the vapour. Wear gloves. |
| Iodine solution | Harmful to the skin. Stains clothes. | Wear gloves. Avoid contact with clothing. |
| Hazard | Chlorine solution |
|---|---|
| Possible harm | Chlorine gas is produced, which is toxic if inhaled. |
| Possible precaution | Make sure the lab is well ventilated and avoid inhaling the gas. |
| Hazard | Bromine solution |
|---|---|
| Possible harm | Toxic bromine vapour is produced. Solution irritates the skin. |
| Possible precaution | Make sure the lab is well ventilated and avoid inhaling the vapour. Wear gloves. |
| Hazard | Iodine solution |
|---|---|
| Possible harm | Harmful to the skin. Stains clothes. |
| Possible precaution | Wear gloves. Avoid contact with clothing. |
Question
Explain whether chlorine will react with sodium fluoride solution.
Chlorine is less reactive than fluorine, so it would not displace fluorine from sodium fluoride solution.
