Chemistry - Salt Analysis Question with Solution | TestHub

The purple complex B is formed when the sulfide ion (S²⁻) from the sodium carbonate extract reacts with sodium nitroprusside, resulting in $[Fe(CN{)}_{5}NOS]$⁴⁻. In this complex, the central metal ion is Iron (Fe) in the +2 oxidation state. Since Fe²⁺ has a $3d^6$ configuration and CN⁻ is a strong field ligand, all six electrons are paired in the $t_{2g}$ orbitals. With zero unpaired electrons ($n=0$), the spin-only magnetic moment is calculated as $\mu =\sqrt{n(n+2)}=0BM$. Therefore, the correct option is (D).