Match the List-I with List-II.
List-I
A. XeO₃
B. XeF₂
C. XeOF₄
D. XeF₆
List-II
I. sp³d; linear
II. sp³; pyramidal
III. sp³d³; distorted octahedral
IV. sp³d²; square pyramidal
Choose the correct answer from the options given below.
Solution:
To determine the hybridization and molecular geometry for each compound, we use the VSEPR theory and calculate the steric number (number of sigma bonds + number of lone pairs) around the central atom (Xenon).
A. XeO₃:
-
Central atom: Xe (Group 18, 8 valence electrons).
-
Oxygen forms double bonds. Each double bond consists of one sigma bond and one pi bond. For steric number calculation, we count only sigma bonds.
-
Number of sigma bonds = 3 (for 3 oxygen atoms).
-
Electrons used in sigma bonding = 3 × 2 = 6 (each oxygen forms a double bond, using 2 electrons from Xe).
-
Remaining valence electrons on Xe = 8 - 6 = 2 electrons.
-
Number of lone pairs = 2 / 2 = 1 lone pair.
-
Steric number = (sigma bonds) + (lone pairs) = 3 + 1 = 4.
-
Hybridization: sp³.
-
Molecular Geometry: Trigonal pyramidal (due to 3 bond pairs and 1 lone pair).
-
Match: A-II.
B. XeF₂:
-
Central atom: Xe (8 valence electrons).
-
Number of sigma bonds = 2 (for 2 fluorine atoms, each forming a single bond).
-
Electrons used in bonding = 2 × 1 = 2.
-
Remaining valence electrons on Xe = 8 - 2 = 6 electrons.
-
Number of lone pairs = 6 / 2 = 3 lone pairs.
-
Steric number = 2 + 3 = 5.
-
Hybridization: sp³d.
-
Molecular Geometry: Linear (due to 2 bond pairs and 3 lone pairs in a trigonal bipyramidal electron geometry, where lone pairs occupy equatorial positions to minimize repulsion).
-
Match: B-I.
C. XeOF₄:
-
Central atom: Xe (8 valence electrons).
-
Number of sigma bonds = 1 (for oxygen double bond) + 4 (for 4 fluorine single bonds) = 5.
-
Electrons used in bonding = 2 (for O) + 4 (for F) = 6.
-
Remaining valence electrons on Xe = 8 - 6 = 2 electrons.
-
Number of lone pairs = 2 / 2 = 1 lone pair.
-
Steric number = 5 + 1 = 6.
-
Hybridization: sp³d².
-
Molecular Geometry: Square pyramidal (due to 5 bond pairs and 1 lone pair in an octahedral electron geometry).
-
Match: C-IV.
D. XeF₆:
-
Central atom: Xe (8 valence electrons).
-
Number of sigma bonds = 6 (for 6 fluorine single bonds).
-
Electrons used in bonding = 6 × 1 = 6.
-
Remaining valence electrons on Xe = 8 - 6 = 2 electrons.
-
Number of lone pairs = 2 / 2 = 1 lone pair.
-
Steric number = 6 + 1 = 7.
-
Hybridization: sp³d³.
-
Molecular Geometry: Distorted octahedral (due to 6 bond pairs and 1 lone pair in a pentagonal bipyramidal electron geometry, the lone pair causes distortion from a perfect octahedron).
-
Match: D-III.
Combining the matches:
A-II, B-I, C-IV, D-III.
This corresponds to option (1).
The final answer is