Question

Which one of the following compound is both colored and paramagnetic?

• A. $ScC{l}_3$
• B. $TiC{l}_4$
• C. $CrC{l}_3$
• D. $CuCl$

Answer 1

Answer: (C)

$CrC{l}_3$

The species which have unpaired electron in d-subshell is both paramagnetic and coloured.

$S{c}^{3+}⟶4s^{0}3d^0$

$T{i}^{4+}⟶4s^{0}3d^0$

$C{r}^{3+}⟶4s^{0}3d^3$

$C{u}^{+}⟶4s^{0}3d^{10}$

$C{r}^{3+}$ is having $3$ unpaired $e^{-}$, thus paramagnetic and hence show color due to transition of these unpaired.