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Question #44263

Difficulty: 8/10 | 🟢 Free

The Question

Consider the octahedral coordination complexes $P = \ce{[NiF6]^{2-}}$ and $Q = \ce{[CoF6]^{3-}}$ at $298\text{ K}$ . Let $x$ and $y$ be the number of unpaired electrons in $P$ and $Q$ , respectively. Identify the correct set of values for $(x, y)$ along with the hybridization of the central metal ion in $P$ and $Q$ respectively.

Options

A.
0, 4, $d^2sp^3$ , $sp^3d^2$
B.
4, 4, $sp^3d^2$ , $sp^3d^2$
C.
4, 0, $sp^3d^2$ , $d^2sp^3$
D.
0, 0, $d^2sp^3$ , $d^2sp^3$

Check Your Answer

Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Mechanism_Trap

Don't get tricked by the process! Learn the mechanical traps used in competitive exam questions.

Concepts Behind This Question

Hund’s Rule of Maximum Multiplicity|Valence Bond Theory Hybridization|Hybridization in Non-Standard Cases

Why This Question Is Tricky

Common Mistakes

The core trap is the assumption that the nature of the ligand (weak vs. strong field) solely dictates the spin state of the complex.

Students often memorize $\ce{F-}$ as a weak-field ligand that always forms high-spin, outer-orbital ( $sp^3d^2$ ) complexes.

They fail to account for the fact that an unusually high oxidation state on the central metal (like Ni(IV)) drastically increases the crystal field splitting energy ( $\Delta_o$ ).

This overrides the weak-field nature of the ligand, forcing the pairing of electrons ( $\Delta_o > P$ ) and resulting in a low-spin, inner-orbital ( $d^2sp^3$ ) complex, overriding the standard application of Hund's rule.

Quick Facts About This Question

Question Information

Subject	Chemistry
Chapter	Structure of Atom - Class 11 Part 1
Concept	Hund’s Rule of Maximum Multiplicity
Difficulty	8
Cognitive Load	7
Target Solve Time	160 sec
Access	Free