Question

A strip of copper is placed in some colourless solutions and the solutions are potassium nitrate, zinc nitrate, calcium nitrate and silver nitrate. One of the solutions turn blue. Which one and give a reason to support your answer.

Answer 1

The blue colour solution is formed in silver nitrate solution (Ag(NO3)2)

As copper being more reactive than silver displaces silver from its solution forming Copper nitrate.

The blue colour is formed due to the formation of copper nitrate

Answer 2

The solution of silver nitrate(AgNO3) turns blue.When copper strip is immersed in the solution, Displacement reaction takes place and copper nitrate is formed which is blue in colour.

AgNO3 + Cu ---CuNO3 + Ag

copper strip only reacts with silver nitrate solution bcs copper can displace silver from its salt solution bcs of its low reactivity.