PYQ + Trends
1. TITLE
This Xenon Fluorides question repeats every year in NEET — See the pattern (XeF2, XeF4, XeF6)
2. THE ACTUAL NEET QUESTION
NEET 2025 — Question
Match List-I with List-II
| List - I | List - II | ||
|---|---|---|---|
| A | $XeO_{3}$ | I | $sp^{3}d$; linear |
| B | $XeF_{2}$ | II | $sp^{3}$; pyramidal |
| C | $XeOF_{4}$ | III | $sp^{3}d^{3}$; distorted octahedral |
| D | $XeF_{6}$ | IV | $sp^{3}d^{2}$; square pyramidal |
Choose the correct answer from the options given below:
A) A-IV, B-II, C-III, D-I
B) A-IV, B-II, C-I, D-III
C) A-II, B-I, C-IV, D-III
D) A-II, B-I, C-III, D-IV
3. OFFICIAL ANSWER
NEET Answer Key: (C)
4. COMPLETE SOLUTION
Concept Explanation:
To solve this, we use the hybridization formula: $H = \frac{1}{2} (V + M - C + A)$,.
* $V$ = Valence electrons of central atom (Xe = 8).
* $M$ = Number of monovalent atoms (F = 1, H = 1). Note: Oxygen is divalent and is not counted in $M$.
* $C/A$ = Cation/Anion charge.
Step-by-Step Breakdown:
-
$XeF_{2}$ (List-I B):
- $H = \frac{1}{2} (8 + 2) = 5$. Hybridization: $sp^{3}d$.
- Electron pairs = 5. Bond pairs (BP) = 2 (Xe-F). Lone pairs (LP) = $5 - 2 = 3$.
- Geometry: Trigonal Bipyramidal.
- Shape: Linear (3 Lone pairs occupy equatorial positions to minimize repulsion),.
- Matches: I
-
$XeF_{6}$ (List-I D):
- $H = \frac{1}{2} (8 + 6) = 7$. Hybridization: $sp^{3}d^{3}$.
- Electron pairs = 7. Bond pairs = 6. Lone pairs = 1.
- Shape: Distorted Octahedral,.
- Matches: III
-
$XeO_{3}$ (List-I A):
- $H = \frac{1}{2} (8 + 0) = 4$. (O is divalent, so M=0). Hybridization: $sp^{3}$.
- Electron pairs = 4. Bond pairs = 3 (sigma bonds to O). Lone pairs = 1.
- Shape: Pyramidal (Similar to Ammonia),.
- Matches: II
-
$XeOF_{4}$ (List-I C):
- $H = \frac{1}{2} (8 + 4) = 6$. (4 F atoms contribute to M). Hybridization: $sp^{3}d^{2}$.
- Shape: Square Pyramidal.
- Matches: IV
Conclusion: A-II, B-I, C-IV, D-III. Correct Option is C.
5. WHY NEET ASKED THIS
Examiner's Intent:
1. Testing Noble Gas Bonding: Xenon fluorides are the classic exception to the "inert gas" rule, and their structures are favorite test topics.
2. Hybridization Formula Application: They want to see if you remember that Oxygen does not count in the $H = \frac{1}{2}(V+M)$ formula for monovalent atoms, a common trap.
3. Lone Pair Repulsion: Specifically for $XeF_{2}$ and $XeF_{6}$, the shape is determined by lone pair placement (VSEPR theory),.
The "Trap":
Students often confuse the geometry (arrangement of electron pairs) with the shape (molecular structure). For example, $XeF_{4}$ has octahedral geometry but square planar shape. In this question, mixing up $XeF_{6}$ (Distorted Octahedral) with regular Octahedral is a potential error point.
6. TREND ANALYSIS
PATTERN ALERT:
Noble gas compounds are a high-yield sub-topic in Chemical Bonding.
| Year | How they asked | Twist |
|---|---|---|
| 2025 | Match List (XeO3, XeF2, XeOF4, XeF6) | Combined 4 molecules into one question. Included Hybridization + Shape. |
| 2024 | Match List (Included XeF4) | Asked to match $XeF_{4}$ to "Square Planar". |
| 2022 | MCQ (Lone Pair Repulsion) | Asking which molecule has max lone pair repulsion ($XeF_{2}$ was the answer). |
| 2021 | Match List (XeF4) | Asked for Geometry/Shape of $SF_{6}$, $BrF_{5}$, $XeF_{4}$. |
| 2016 | MCQ (XeF4 specific) | Direct question on Geometry & Hybridization of $XeF_{4}$. |
Prediction for NEET 2026:
Expect a question focusing on Iso-structural pairs involving Xenon. For example: "Which molecule is isostructural with $XeF_{2}$?" (Answer: $I_{3}^{-}$ or $ICl_{2}^{-}$) or a deep dive into $XeOF_{4}$ specifically.
7. SIMILAR QUESTIONS TO PRACTICE
"If you understood this, you can solve:"
* NEET 2024 Q11: Match List-I ($XeF_{4}$) with List-II (Square Planar).
* NEET 2022 Q22: Amongst $ClF_{3}$, $IF_{5}$, $SF_{4}$, $XeF_{2}$, which has maximum 'lone pair - lone pair' repulsion? (Answer: $XeF_{2}$ with 3 lone pairs).
* NEET 2016 Q41: The correct geometry and hybridization for $XeF_{4}$ are? (Answer: Octahedral, $sp^{3}d^{2}$).
8. QUICK REVISION FOR THIS TYPE
For Xenon Fluoride questions, always memorize this table:
| Molecule | Hybridization | Bond Pairs (BP) | Lone Pairs (LP) | Shape |
|---|---|---|---|---|
| $XeF_{2}$ | $sp^{3}d$ | 2 | 3 | Linear |
| $XeF_{4}$ | $sp^{3}d^{2}$ | 4 | 2 | Square Planar |
| $XeF_{6}$ | $sp^{3}d^{3}$ | 6 | 1 | Distorted Octahedral |
| $XeO_{3}$ | $sp^{3}$ | 3 | 1 | Pyramidal |
Watch out for:
* $XeF_{2}$ has 3 lone pairs (maximum repulsion cases).
* $XeF_{4}$ is Square Planar (not Tetrahedral).
* $XeF_{6}$ is Distorted Octahedral (due to 1 LP).
9. NCERT BASE
This question tests: NCERT Class 11, Chapter 4 (Chemical Bonding), Section 4.6 (Hybridisation) and Table 4.7 (Shapes of Molecules with Lone Pairs).
Also covered in Class 12, Group 18 Elements.
10. CTA
All PYQs from this chapter → Chemical Bonding & Molecular Structure Guide
Practice similar questions → Mock exams
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