Displacement Reactions

Question 1

What are displacement reactions used to prove ?

Answer 1

They are used to prove the oxidising ability of the halogens

Question 2

What happens in a displacement reactions ?

Answer 2

It is a redox reaction
Where are more reactive halogen ( better oxidising agent) takes the okach of a less reactive hallide ion ( better reducing agent)

Question 3

How would you show which is the best oxidising agent ?

Answer 3

Add chlorine water Cl2 (aq) to test tube containing NaCl,NaBr and NaI
All solution will start off colourless
Cl2 + NaCl will show no visible change
Cl2 + NaBr will show and orange / yellow solution forming (bromine ions oxidised)
Cl2 + NaI will form a brown solution (iodide ions oxidised)

Question 4

Write a half equation for the displacement of bromine in NaBr by Cl2 ?

Answer 4

Notes

Question 5

What would occur if you added Br2 instead of Cl2 ?

Answer 5

All solution will start of colourless at first
There will be no visible change for NaCl and NaBr because chlorine is less reactive than bromine and bromine has the same reactivity as another bromine
With NaI : a brown solution should form as the iodide gets oxidised due to iodine being more reactive than bromine

Question 6

What would occur if you added I2 instead of Br2 and Cl2 ?

Answer 6

Expect no reaction to occur because iodine is not a good oxidising agent