Question

What happens when a piece of zinc metal is added to copper sulphate solution?
A) Decomposition reaction
B) Displacement reaction
C) Double displacement reaction
D) Precipitation reaction

Answer 1

Hint: The answer can be approached directly based on the concept that when zinc is added to copper sulphate solution, it has capacity to form zinc sulphate solution. This concept gives what type of reaction it is undergoing.

Complete Solution :
Now, let us see what happens when zinc is added to copper sulphate solution.
We know the fact that copper sulphate solution is blue in colour and the reaction that happens when the zinc metal is added is that the colour of the solution from blue changes to colourless.
- Here, in this process zinc is more reactive metal because it has a greater tendency to lose electrons and form positive ions compared to that of copper metal and therefore, this displaces copper from the copper sulphate solution and forms zinc sulphate.
- Therefore, the type of reaction that it undergoes, based on these facts, it can be said that it is the displacement reaction because in changing from copper sulphate (blue coloured solution) to zinc sulphate (colourless solution), the very reactive zinc metal displaces copper from its solution.
The reaction is as shown below,
\[Zn(s)+CuS{{O}_{4}}(aq)\to ZnS{{O}_{4}}(aq)+Cu(s)\]

So, the correct answer is “Option A”.

Note: Note that displacement reaction in general means that it is a type of chemical reaction in which one element is replaced by another element and this occurs mostly when one element is more reactive which gives a stable product..