Q.

Which of the following is an example of simple displacement

1 the electrolysis of water  
2 the burning of methane  
3 the reaction of a metal with an acid  
4 the reaction of two salt solutions to form a precipitate  

Ans.

(3)

The displacement reaction is the one wherein the atom or a set of atoms is displaced by another atom in a molecule. For instance, when iron is added to a copper sulphate solution, it displaces the copper metal.

A + B - C  A - C + B