What happens when iron nails are put into copper sulphate solution ?

25 What will happen if a strip of zinc is kept immersed in a solution of copper sulphate ? 26 What will happen if a strip of copper is kept immersed in a solution of silver nitrate (AgNO₃)? 28 How would you show that silver is chemically less reactive than copper ? 29 Give reasons for the following:

Blue colour of copper sulphate solution is destroyed when iron filings are added to it.