Question

Magnetic moment of $\left[ Ni ( CN )_4\right]^{2-}$ is zero but that of $\left[ Ni \left( H _2 O \right)_4\right]^{2+}$ is $2.83 BM$ It is because of

• A. Different oxidation state of $Ni$ in two complexes
• B. $CN ^{-}$is a strong ligand making two unpaired electrons in $Ni ^{2+}$ paired while in $\left[ Ni _2\left( H _2 O \right)_4\right]^{2+}$, two electrons remain unpaired $H _2 O$ being weak ligand
• C. Both (a) and (b)
• D. None of the above

Answer 1

Answer: (B)

Correct answer is (b) $CN ^{-}$is a strong ligand making two unpaired electrons in $Ni ^{2+}$ paired while in $\left[ Ni _2\left( H _2 O \right)_4\right]^{2+}$, two electrons remain unpaired $H _2 O$ being weak ligand