Question

Brightly polished iron nails are placed in copper nitrate solution. Describe all that you will observe after an hour.

Answer 1

Copper nitrate solution is blue in colour. The iron nail will react with copper nitrate to form Iron(II) nitrate which will be further oxidised to Iron (III) nitrate. Thus, iron metal displaces copper metal from its salt solution. The colour of the solution will fade and turn yellowish-brown and iron nail will be covered by reddish copper metal.
Cu(NO₃)₂ + Fe $\to$ Fe(NO₃)₂
Fe(NO₃)₂ $\stackrel{oxidation}{\to }$ Fe(NO₃)₃