Question

why does the colour of copper sulphate solution changes when an iron nail is dipped in it? write the chemical reaction involved

Answer 1

The colour of copper sulphate solution changes when an iron nail is dipped in it because iron is more reactive than copper.

A substance which releases ${ H }^{ + }$ ions are called acids.

When an "iron nail" dips into the solution of "copper sulphate" than iron, the copper sulphate displaces copper because "iron" is "more reactive" than "copper".

Hence the colour of the solution for copper sulphate changes.

The chemical reaction is as follows.

$Fe(s)\quad +\quad Cu{ SO }_{ 4 }(aq)\quad \rightarrow \quad Fe{ SO }_{ 4 }(aq)\quad +\quad Cu(s)$

Answer 2

Iron nail when immersed in the solution of copper sulphate will undergo certain reactions. Here iron displaces copper from copper sulphate. and the colour of copper sulphate will change from blue to pale green

Explanation:

• Iron nail  when immersed in the solution of copper sulphate.

• Here iron will displace copper from the solution of copper sulphate because  of the reason that iron is more reactive than copper.

• The  colour of copper sulphate solution  will change from blue to pale green.

Reaction involved :-

This reaction shows the displacement of Fe and Cu

$CuSO4 (aq) + Fe (s)$ → $FeSO4 (aq) + Cu (s)$

In this reaction

The displacement takes place in following two steps :-

$Cu^{2+} + 2e = Cu^{0}$ (here re­duc­tion takes place, Cu²⁺ is the ox­i­dizing agent)

$Fe^{0} +2e = Fe^{2+}$(here ox­i­da­tion takes place, Fe⁰ is the re­duc­ing agent)

• This reaction is a double displacement reaction and redox reaction. where oxidation and reduction both takes place simultaneously.

• According to electrochemical series iron is more reactive than copper

• So it displaces copper from the copper sulphate solution.

Here iron passes into the solution as Fe (II) forming the ferrous sulphate solution.

#SPJ6