question_answer

Choose the correct statement.

A)  \[{{[Co{{(N{{H}_{3}})}_{6}}]}^{2+}}\] is oxidised to diamagnetic \[{{[Co{{(N{{H}_{3}})}_{6}}]}^{3+}}\] by the oxygen in air

B)  Tetrahedral complexes are more stable than octahedral complexes

C)  \[{{[Fe{{(CN)}_{6}}]}^{3-}}\] is stable but \[{{[Fe{{F}_{6}}]}^{3-}}\] is unstable

D)  The \[{{[Cu{{[N{{H}_{3}})}_{4}}]}^{2+}}\] ion has a tetrahedral geometry and is diamagnetic

Correct Answer: A

Solution :

                 \[{{[Co{{(N{{H}_{3}})}_{6}}]}^{2+}}=[Ar]\] (No unpaired electron, so diamagnetic)  Tetrahedral complexes are less stable than octahedral complexes.  \[{{[Fe{{(CN)}_{6}}]}^{3-}}\] and \[{{[Fe{{F}_{6}}]}^{3-}}\] both are stable but former is more stable.  \[{{[Cu{{(N{{H}_{3}})}_{4}}]}^{2+}}\] has square planar geometry and is paramagnetic.