Question

Which of the following complex is paramagnetic with two unpaired electrons ?

• A. $K_{3}\left[Fe \left(\right. CN \left(\left.\right)_{6}\right]$
• B. $K_{2}\left[NiCl_{4}\right]$
• C. $K_{2}\left[CoCl_{4}\right]$
• D. $\left(Na\right)_{2}\left[Ni \left(\right. CN \left(\left.\right)_{4}\right]$

Answer 1

Answer: (B)

$K_{2}\left[NiCl_{4}\right]Ni^{+ 2}$
$\left(Cl\right)^{-}\left(\right.WFL\left.\right)$ . So No pairing of $e^{-}$ takes place. Hence it is paramagnetic with two unpaired $e^{-}$