Question

Iron nails are placed in copper sulphate solution. Write word equations for the reactions involved.

Answer 1

Hint: To solve this question, we must first recall the reactivity series of metals and keep in mind the relative position of Iron and Copper. We know that the most reactive metals are placed higher up in the series and the activity decreases down the series.

Complete step by step answer:
If we dip iron nails in Copper sulphate solution, we see that gradually the blue colored Copper sulphate solution becomes light green in color.
Here we should note that Iron is placed at a higher position than copper in the activity series of metals, that means Iron is more reactive than Copper. Hence, we can expect that a simple displacement reaction has taken place and Iron has displaced Copper sulphate to form Iron sulphate. One can also find reddish brown metallic Copper deposits on the iron nails or is deposited at the bottom of the container.
\[Iron(Fe)\, + \,Copper\,sulphate(CuS{O_4}) \to Iron\,sulphate(FeS{O_4}) + Copper(Cu)\]

Additional information:
Since, we can see that iron is more reactive than copper because it is placed above copper in the electrochemical series of substances (or the reactivity series of metals), we can conclude that Iron can reduce Copper from its salt solution to its elemental form.
Also, we can see that iron has been oxidized from 0 oxidation state to a +2 state whereas copper has been reduced by iron from +2 state to its elemental form of 0 oxidation state.

Note: Here we should remember the reason for the difference in reactivity of metals. It is due to the difference in stability of their electron configurations as atoms and as ions. As they are all metals they will form positive ions when they react. Potassium is the most reactive and platinum is the least reactive metal known.