Question

Which of the following compounds is coloured?

• A. $Ti Cl_3$
• B. $FeCl_3$
• C. $CoCl_2$
• D. All of these

Answer 1

Answer: (D)

All of these

Answer 2

The compounds having metal ions with unpaired electrons, are coloured. Thus, in $TiCl _{3}$ $Ti ^{3+}=[ Ar ] 3 d^{1}$ (One unpaired electron) in $FeCl _{3}$ $Fe ^{3+}=[ Ar ] 3 d^{5}$ (Five unpaired electrons) in $CoCl _{2}$ $Co ^{2+}=[ Ar ] 3 d^{7}$ (Three unpaired electrons) Hence, all compounds are coloured.