Question

What happens when?
(A) Dilute sulphuric acid is poured on a copper plate.
(B) Iron nails are placed in copper sulphate solution.
Write word equations of the reaction involved.

Answer 1

Hint: For part (a) we should keep the reactivity series in mind. An element below another element in the reactivity series will not have any reaction with the elements above it.
In part (b), we should note that iron is placed above Copper in the reactivity series, therefore, a reaction will take place.

Complete Solution :
a) When dilute sulphuric acid is poured on a copper plate, no reaction will take place. This is because Copper (Cu) lies below hydrogen in the reactivity series.
\[Cu+{{H}_{2}}S{{O}_{4}}\left( dil. \right)\xrightarrow{{}}\text{No reaction}\]

(b) Iron reacts with copper as it is placed above it in the reactivity series. When iron nails are placed in copper sulphate solution, the color of copper sulphate solution changes from blue to green. This is due to the displacement of copper in copper sulphate by iron. When copper gets deposited on the iron nail, a green solution is formed - ferrous sulphate (\[FeS{{O}_{4}}\])
\[\begin{align}
 & CuS{{O}_{4}}+Fe\xrightarrow{{}}FeS{{O}_{4}}+Cu \\
 & \left( Blue \right)\text{ }\left( Green \right) \\
\end{align}\]

Note: We can use the reactivity series to determine the products of single displacement reactions, where, if metal A is higher in the series, it will replace another metal B in a solution. Apart from predicting whether a metal will displace another metal, the reactivity series also helps us to predict the outcome of reactions between metals and water, and metals and acids.