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Question #44325

Difficulty: 8/10 | 🟢 Free

The Question

The ability of oxygen to stabilize high oxidation states of transition metals often exceeds that of fluorine. This is because oxygen can form multiple bonds (pπ−dπp\pi-d\pi) with the metal, whereas fluorine stabilizes high oxidation states primarily through high lattice energy in the solid state.

Consider the highest stable binary oxide and the highest stable binary fluoride of Manganese at 298 K298\text{ K}. Let OoxO_{ox} = Oxidation state of Mn in its highest binary oxide. Let OFO_{F} = Oxidation state of Mn in its highest binary fluoride. Let NπN_{\pi} = Total number of pπ−dπp\pi-d\pi bonds in one discrete molecule of the highest binary oxide. Let YY = Number of unpaired electrons in the central metal ion of the highest binary fluoride. Let CoxC_{ox} = Coordination number of Mn in the highest binary oxide. Let CFC_{F} = Coordination number of Mn in the solid-state structure of the highest binary fluoride.

Calculate the value of the expression: (Oox×OF)+(Nπ×Y)−Cox+CF(O_{ox} \times O_{F}) + (N_{\pi} \times Y) - C_{ox} + C_{F}.

Options

  • A.

    48

  • B.

    46

  • C.

    42

  • D.

    69

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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

d-block Variable Oxidation States|Stability of High O.S. Fluorides/Oxides|Lattice Energy Factors

Why This Question Is Tricky

Common Mistakes

This question tests the 'Chemical Exception' where students often incorrectly assume that fluorine, being the most electronegative element, will always stabilize the highest oxidation state of a transition metal.

The hidden variable is the bonding mechanism: oxygen stabilizes extreme oxidation states (like +7 in Mn) via covalent pπ−dπp\pi-d\pi multiple bonding, which minimizes steric crowding (coordination number 4).

Fluorine can only form single bonds, relying on high lattice energy for stabilization, but is sterically capped (coordination number 6), limiting Mn to +4 in \ce{MnF4}.

The problem also traps students who assume \ce{MnF4} is a discrete tetrahedral molecule rather than an octahedral polymer in the solid state.

Quick Facts About This Question

Question Information

SubjectChemistry
ChapterClassification of Elements and Periodicity in Properties - Class 11 Part 1
Conceptd-block Variable Oxidation States
Difficulty8
Cognitive Load7
Target Solve Time160 sec
AccessFree