Question

Chloride of which of the following element is colored?

• A. Hg
• B. Ag
• C. Co
• D. Zn

Answer 1

Answer: (C)

In $CoC{l}_3,Co$ is in $+3$ state
$C{o}^{3+}=1s^2,2s^{2}2p^6,3s^{2}3p^{6}3d^6,4s^{\circ }$
4 unpaired electrons, so it will be coloured.