Question

The correct order of the spin-only magnetic moment of metal ions in the following low spin complexes, $[V(CN)_6]^{4-}, [Fe(CN)_6]^{4-}, [Ru (NH_3)_6]^{3+},$ and $[Cr(NH_3)_6]^{2+}$, is :

• A. $V^{2+} > Cr^{2+} > Ru^{3+} > Fe^{2+}$
• B. $V^{2+} > Ru^{3+} > Cr^{2+}> Fe^{2+}$
• C. $Cr^{2+} > V^{2+} > Ru^{3+} > Fe^{2+}$
• D. $ Cr^{2+} > Ru^{3+} > Fe^{2+} > V^{2+} $

Answer 1

Answer: (A)

Solution:- $( A ) V ^{2+}> Cr ^{2+}> Ru ^{3+}> F e ^{2+}$
According to equations, all the complexes are low spin. No. of Complex Configuration unpaired electrons $\left[\begin{array}{lll}{\left[ V ( CN )_{6}\right]^{4-}} & t _{2 g }^{3} e _{ g }^{0} & 3\end{array}\right.$
No. ot Complex Configuration unpaired electrons $\left[ V ( C N )_{6}\right]^{4-} t _{ 2 g }^{3} e _{ g }^{0}$
3
$\left.\left[ C r ( N H )_{3}\right)_{6}\right]^{2+} t _{2 g }^{4} e _{ g }^{0}$
2
$\left[ R u \left( N H _{3}\right)_{6}\right]^{3+} t _{2 g }^{5} e _{ g }^{0}$
1
$\left[ F e ( C N )_{6}\right]^{4-} t _{2 g }^{6} e _{ g }^{0}$
0