Which solution will turn blue when a copper plate is plunged?

Question

There are colourless solution of some salt in four separate test tubes. We plunge a piece of copper plate in each of the test tubes. Suppose the following salts were in the test tubes. Which solution will change to form a blue solution?

a) NaCl b) AgNO3 c) Cd(NO3)2 d) ZnSO4

Answer 1

Copper is going into solution so it is being oxidised to Cu2+.

Think reactivity series. Which of these solutions have cations of metals less reactive than copper?

Answer 2

Your skin