question_answer

Assertion :\[{{[Co{{F}_{6}}]}^{3-}}\]is paramagnetic. Reason (R):\[C{{o}^{3+}}\]has\[3{{d}^{6}}\]outer electronic configuration. The unpaired electrons do not pair up because of weak field provided by\[{{F}^{-}}\].

A)  A and R both are correct and R is the correct explanation of A.

B)  A and R both are correct but R is not the correct explanation of A.

C)  A is incorrect while R is correct.

D)  A and R both are incorrect.

Correct Answer: A

Solution :

                 In complex\[{{[Co{{F}_{6}}]}^{3-}}\]oxidation number of\[Co=+3\] Electronic configuration of \[C{{o}^{3+}}=1{{s}^{2}},2{{s}^{2}},2{{p}^{6}},3{{s}^{2}},3{{p}^{6}},3{{d}^{6}}\] In \[C{{o}^{3+}}\] In\[C{{o}^{3+}}\]number of unpaired electrons is four, is the ligand of weak field. Hence it doesn't paired up electrons of d -orbital. So, In \[{{[Co{{F}_{6}}]}^{3-}}\] So,\[{{[Co{{F}_{6}}]}^{3-}}\]is paramagnetic. \[C{{o}^{3+}}\]has\[3{{d}^{6}}\]outer electronic configuration, but four unpaired electrons don't pair up because of weak field provided by\[{{F}^{-}}\]. Hence, assertion is correct and reason is the correct explanation of assertion