Question

Out of $TiF _{6}^{2-}, CoF _{6}^{3-}, Cu _{2} Cl _{2}$ and $NiCl _{4}^{2-}$ (At. no. $Z$ of $Ti =22, Co =27, Cu =29$, $Ni =28$ ), the colourless species are

• A. $TiF^{2-}_6$ and $CoF^{3-}_6$
• B. $Cu_2Cl_2$ and $NiCl^{2-}_4$
• C. $Cu_2Cl_2$ and $ TiF^{2-}_6$
• D. $CoF^{3-}_6 $ and $NiCl^{2-}_4$

Answer 1

Answer: (C)

$TiF _{6}^{2-} Ti ^{+4} \rightarrow[ Ar ] 0$ unpair $e ^{-} \Rightarrow$ Dimagnetic/ colourless
$CoF _{6}^{3-} Co ^{+3} \rightarrow[ Ar ] 3 d ^{6} 4$ unpair e ${ }^{-} \Rightarrow$ Paramagnetic/ coloured
$Cu _{2} Cl _{2} Cu ^{+} \rightarrow[ Ar ] 3 d ^{10} 0$ unpair $e ^{-} \Rightarrow$ Dimagnetic/ colourless
$NiCl _{4}^{2-} Ni ^{+2} \rightarrow[ Ar ] 3 d ^{8} 2$ unpair $e ^{-} \Rightarrow$ Paramagnetic/ coloured