You want to store a freshly made solution of copper sulphate. You have 4 options with you. Which of these is preferable to ensure that the solution remains intact?
Reduction potentials:
Zn2+/Zn= −0.76
Mg2+/Mg= −2.37
Cu2+/Cu= 0.34
Ag+/Ag= 0.8
Sn2+/Sn= 0.16