Question

Among Fe, Mn, Co and Cr, element having highest value of \(E _{M^{3+}/M^{2+}} ^{o}\) form a complex \([M(CN)_6]^{3-}\), then find the number of electrons in eg set of orbital

(1) 0

(2) 1

(3) 2

(4) 4

Answer 1

Correct option is : (1) 0

\(E _{Fe^{3+}/Fe^{2+}} ^{o} = 0.77 V\)

\(E _{Co^{3+}/Co^{2+}} ^{o} = 1.97 V \)

\(E _{Cr^{3+}/Cr^{2+}} ^{o} = -0.41 V\)

\(E _{Mn^{3+}/Mn^{2+}} ^{o} = 1.57 V\)

Cobalt having maximum value of \(E _{Co^{3+}/Co^{2+}} ^{o} \) i.e. 1.97 V

Complex compound should be [Co(CN)₆]^3–

Co³⁺ ⇒ [Ar]3d⁶ 4s⁰

\(\Delta o\) > P as CN^– is a SFL with Co³⁺ ion

\(t _{2g}^{6} e_{g}^{0}\)

Number of electrons in eg set of orbitals = 0