Question

Match List I with List II:

List I - Complex		List II - Crystal Field Splitting energy (△0)
A.	[Ti(H2O)6]2+	I.	– 1.2
B.	[V(H2O)6]2+	II.	– 0.6
C.	[Mn(H2O)6]3+	III.	0
D.	[Fe(H2O)6]3+	IV.	– 0.8

Choose the correct answer from the options given below:

• A. A-II, B-IV, C-III, D-I
• B. A-IV, B-I, C-II, D-III
• C. A-II, B-IV, C-I, D-III
• D. A-IV, B-I, C-III, D-II

Answer 1

The Correct Option is B

To solve this question, we need to determine the correct match between the complexes in List I and their corresponding Crystal Field Splitting energy (Δ₀) in List II. Let's analyze each complex:

1. [Ti(H₂O)₆]²⁺: Titanium in this complex is in a +2 oxidation state, leading to Ti²⁺ with a d² configuration. The Crystal Field Splitting energy, Δ₀, is generally determined experimentally; however, we know that Ti²⁺ complexes often have small splitting energies. Thus, it matches with a smaller negative value.
2. [V(H₂O)₆]²⁺: Vanadium in a +2 oxidation state corresponds to V²⁺ with a d³ configuration. This configuration typically results in higher splitting due to more electron-electron repulsion in the t_2g orbitals. So, this matches with a slightly larger negative value.
3. [Mn(H₂O)₆]³⁺: Manganese in a +3 oxidation state results in Mn³⁺ with a d⁴ configuration. However, Mn³⁺ has a well-known configuration where Jahn-Teller distortion occurs, typically resulting in lower or zero stabilization energy, especially in octahedral symmetry.
4. [Fe(H₂O)₆]³⁺: Iron in a +3 oxidation state forms Fe³⁺ with a d⁵ configuration. This usually results in moderate splitting values because all d orbitals are singly occupied, leading to symmetry and a lower energy state.

Considering these observations and typical crystal field stabilization orderings, we can construct matches:

• [Ti(H₂O)₆]²⁺ should correspond to –0.8 (IV).
• [V(H₂O)₆]²⁺ should correspond to –1.2 (I).
• [Mn(H₂O)₆]³⁺ should correspond to –0.6 (II).
• [Fe(H₂O)₆]³⁺ should correspond to 0 (III).

Therefore, the correct match from the given options is:

A-IV, B-I, C-II, D-III

This solution is based on understanding the principles of Crystal Field Theory, which helps in predicting the splitting energy of d-orbitals in metal complexes depending on their oxidation states and electron configurations.