Four successive members of the first series of transition metals are listed below. For which one of the of standard potential `(E_(M^(2+)//M)^(@))` value has a positive sign ?

Options

A. Co(Z=27)
B. Ni(Z=28)
C. Cu(Z=29)
D. Fe(Z=26)

Answer

C

Explanation

`{:("Elements",Co,Ni,Cu,Fe),(,E^(@)M^(2+)//M:,-0.28,-0.25,+0.44):}`