Displacement Reaction

Question 1 What are displacement reactions?

Question 2 Which metal is more reactive:iron or zinc?

Question 3 What would you observe when a strip of zinc is dipped in copper sulphate solution?

Question 4 What would you observe when a strip of iron is dipped in copper sulphate solution?

Question 5 What would you observe when a strip of zinc is dipped in iron sulphate solution?

Question 6 Can copper displace iron from iron sulphate solution?Gove reason for your answer?

Question 7 Can copper displace zinc from zinc sulphate solution.Give reason for your answer?

Displacement Reaction

A more reactive metal displaces a less reactive metal from its salt solution.

When a more reactive metal is placed in the salt solution of a less reactive metal,then the more reactive metal displaces the less reactive metal from its salt solution.

1)Reaction of iron metal with copper sulphate solution

When a strip of iron metal is placed in a copper sulphate solution for sometime, then the blue colour of copper sulphate solution fades and a red-brown coating of  copper metal is deposited on the iron strip.

Fe (s) + CuSO₄  (aq) ——> FeSO₄  (aq) + Cu (s)

Grey         Blue                         Greenish soln      Red-brown

The solution turns greenish due to the formation of iron sulphate.A more reactive metal iron is displacing a less reactive metal copper from its salt solution,copper sulphate solution.

The blue colour of copper sulphate solution changes to greenish due to the formation of iron sulphate.The copper metal produced in this displacement reaction forms a red-brown coating over the iron strip.

A less reactive metal cannot displace a more reactive metal from its salt solution

FeSO₄  (aq) + Cu (s) ——–>No displacement reaction

Displacement reaction does not occur because copper metal is less reactive than iron metal.So a less reactive metal copper cannot displace a more reactive metal iron from its salt solution,iron sulphate solution.

2)Reaction of zinc metal with copper sulphate solution

When a strip of zinc metal is placed in a copper sulphate solution for sometime,then the blue colour of copper sulphate solution fades and a red-brown coating of  copper metal is deposited on the zinc strip.

CuSO₄  (aq) + Zn (s) —-> Cu (s) + ZnSO₄ (aq)

Blue                 Silvery           red          Colourless

                          White           Brown

A more reactive metal zinc is displacing a less reactive metal copper from its salt solution,copper sulphate solution.

The blue colour of copper sulphate solution gradually disappears due to the formation of zinc sulphate.The copper metal produced in this displacement reaction forms a red-brown coating over the zinc strip.

A less reactive metal cannot displace a more reactive metal from its salt solution.

Cu (s) + + ZnSO₄ (aq) —–> no reaction

3)Reaction of zinc metal with iron sulphate solution

When a strip of zinc metal is placed in iron sulphate solution,then a displacement reaction take place to form zinc sulphate solution and iron metal.

FeSO₄ + Zn ———->  ZnSO₄  + Fe 

Zinc metal displaces iron metal from iron sulphate solution.This displacement reaction takes place because zinc is more reactive than iron.