Question

The green coloured complex ion of nickel in its aqueous solution is

• A. $\left[ Ni ( en )_{3}\right]^{2+}$
• B. $\left[ Ni \left( H _{2} O \right)_{2}( en )_{2}\right]^{2+}$
• C. $\left[ Ni \left( H _{2} O \right)_{4}( en )\right]^{2+}$
• D. $\left[ Ni \left( H _{2} O \right)_{6}\right]^{2+}$

Answer 1

Answer: (D)

In complex $\left[ Ni \left( H _{2} O \right)_{6}\right]^{2+}$ the strong ligand is absent. Thus, electrons do not go for pairing and two unpaired $e^{-}$ are present in $Ni ^{2+}$ complex. Hence, is a coloured complex.