question_answer

Which of the following compound is expected to be coloured?

A)  \[A{{g}_{2}}S{{O}_{4}}\]                              

B)  \[Cu{{F}_{2}}\]

C)  \[Mg{{F}_{2}}\]                               

D)  CuCI

Correct Answer: A

Solution :

                (a,b)\[_{47}Ag=[Kr]\,\,4{{d}^{10}}5{{s}^{1}}\] \[A{{g}_{2}}S{{O}_{4}}\Rightarrow A{{g}^{2+}}=[Kr]\,4{{d}^{9}}\]                                 Due to presence of one unpaired electron it is coloured. Its colour is nearly, red and orange. \[_{29}Cu=[Ar]\,3{{d}^{10}}\,4{{s}^{1}}\] \[Cu{{F}_{2}}\Rightarrow C{{u}^{2+}}=[Ar]\,\,3{{d}^{9}}\]                                                      Due to presence of one unpaired electron, it is also coloured. Its colour is white or green. \[_{12}Mg=[Ne]\,\,3{{s}^{2}}\] \[Mg{{F}_{2}}=M{{g}^{2+}}=[Ne]\] Due to absence of unpaired electron, it is colourless. \[CuCl\Rightarrow C{{u}^{+}}=[Ar]\,\,3{{d}^{10}}\]                                 Due to absence of unpaired electron, it is colourless.