Question

In $Ti{F}_6^{2-},Co{F}_6^{3-},C{u}_{2}C{l}_2$ and $NiC{l}_4^{2-}$ the colourless species is (Atomic number Ti = 22, Co = 27, Cu = 29, Ni = 28)

• A. $Ti{F}_6^{2-}$ and $C{u}_{2}C{l}_2$
• B. $C{u}_{2}C{l}_2$ and $NiC{l}_4^{2-}$
• C. $Ti{F}_6^{2-}$ and $Co{F}_6^{3-}$
• D. $Co{F}_6^{3-}$ and $NiC{l}_4^{2-}$

Answer 1

Answer: (A)

$Ti{F}_6^{2-},Co{F}_6^{3-},C{u}_{2}C{l}_2$ and $NiC{l}_4^{2-}$ give $T{i}^{4+},C{o}^{3+},C{u}^{+}$ and $N{i}^{2+}$ ions respectively.
$T{i}^{4+}=3d^0,{45}^0$
$C{o}^{3+}=3d^6,{45}^0$
$C{u}^{+}=3d^{10},{45}^0$
$N{i}^{2+}=3d^8,{45}^0$
$Ti{F}_6^{2-}$ and $C{u}_{2}C{l}_2$ species are colourless due to the absence to unparied electron in $T{i}^{4+}$ and $C{u}^{+}$ ions.