The standard reduction potentials of `Ni^(2+)|Ni, Cr^(3+)|Cr, Ag^(+)|Ag, Fe^(2+)|Fe` electrodes are `-0.24, -0.74, +0.80 and -0.44V`, respectively. Arrange `Ni, Cr, Ag and Fe` in increasing order of their reducing power and give reasons.

Explanation

Electrode having lower standard reduction potential will have higher tendency to get oxidised i.e., it will have higher reducing property. The increasing order of standard reduction potential of the given electrodes is :
`E_(Ag^(+)|Ag)^(@)ltE_(Ni^(2+)|Ni)^(@)ltE_(Fe^(2+)|Fe)lt E_(Cr^(3+)|Cr)`. Hence the order of increasing reducing power of the metals : `Cu lt Fe lt Ni lt Ag`.