Question

On immersing an iron nail in CuSO₄ solution for a few minutes, you will observe

• A. No reaction takes place
• B. The colour of the solution fades away
• C. The surface of iron nails acquires a black coating
• D. The colour of the solution changes to green

Answer 1

The correct option is D

The colour of the solution changes to green

Explanation for Correct answer:

Option D The colour of the solution changes to green

• The reaction is where the atom or a set of atoms is displaced by another atom in a molecule.$\left(\mathrm{A}+\mathrm{BC}\to \mathrm{AC}+\mathrm{B}\right)$
• When an Iron nail is immersed in the blue colour of Copper sulphate fades away and a green colour solution of Iron sulphate is formed.
• Because of the high reactivity of Iron, it can displace the Copper ions in the solution and these Copper ions get deposited on Iron nails.

$\underset{\mathrm{Copper}\mathrm{sulphate}}{{\mathrm{CuSO}}_4\left(\mathrm{aq}\right)}+\underset{\mathrm{Iron}}{\mathrm{Fe}\left(\mathrm{s}\right)}\to \underset{\mathrm{Iron}\mathrm{sulphate}}{{\mathrm{FeSO}}_4\left(\mathrm{aq}\right)}+\underset{\mathrm{Copper}}{\mathrm{Cu}\left(\mathrm{s}\right)}$

• Hence option D is correct.