Question

Which of the following statements are correct?
(A) $[Ni(H_{2}O{)}_6{]}^{2+}$ and $[Ni(N{H}_3{)}_6{]}^{2+}$ have same value of CFSE
(B) $[Ni(H_{2}O{)}_6{]}^{2+}$ and $[Ni(N{H}_3{)}_6{]}^{2+}$ have same value of magnetic moment
(C) $[Ni(H_{2}O{)}_6{]}^{2+}$ and $[Ni(N{H}_3{)}_6{]}^{2+}]$ have same hybridisation of nickel

• A. (A) and (C) only
• B. (B) and (C) only
• C. (A) and (B) only
• D. All of these

Answer 1

Answer: (B)

(A) Ammonia is a stronger field ligand than water. So ${\left[Ni{\left(N{H}_3\right)}_6\right]}^{2+}$ will have higher $CFSE$ than ${\left[Ni{\left(H_{2}O\right)}_6\right]}^{2+}$

(B) Both complexes ${\left[Ni{\left(H_{2}O\right)}_6\right]}^{2+}$ and ${\left[Ni{\left(N{H}_3\right)}_6\right]}^{2+}$ have sp ${}^3{d}^2$ hybridisation with two unpaired electrons. So, they possess same magnetic moment ('spin only')