Chemistry Multiple Choice Questions on “Valence Shell Electron Pair Repulsion (VSEPR) Theory”.
1. Which of the following is correct regarding repulsive interaction?
a) Lone pair-Lone pair is greater than Lone pair-Bond pair is greater than Bond pair-Bond pair
b) Lone pair-Lone pair is less than Lone pair-Bond pair is less than Bond pair-Bond pair
c) Lone pair-Bond pair is greater than Lone pair-Lone pair is greater than Bond pair-Bond pair
d) Lone pair-Lone pair is greater than Lone pair-Bond pair is less than Bond pair-Bond pair
Answer: a
Clarification: The repulsive interactions follow the above order. The lone pairs are localized on the central atom, each bonded pair is shared between two atoms. So, the lone pair electrons in a molecule occupy more space as compared to the bonding pairs of electrons.
2. The shape of the molecule depends on the _______
a) adjacent atom
b) valence electrons
c) surroundings
d) atmosphere
Answer: b
Clarification: As the postulate of Valence Shell Electron Pair Repulsion Theory (VSEPR), the shape of the molecule depends on the number of valence shell electron pairs around the atom (both bonded and non-bonded).
3. The shape a molecule occupies allows to minimize repulsions among them and maximize the space between them.
a) True
b) False
Answer: a
Clarification: As the postulate of Valence Shell Electron Pair Repulsion Theory (VSEPR), a molecule tends to form a shape or orientation that has little repulsion comparatively and the higher distance between the electron pairs comparatively.
4. What is the shape of the molecule NH3?
a) Square pyramidal
b) V-shape
c) Triagonal pyramidal
d) Tetrahedral
Answer: c
Clarification: The molecule NH3 has a lone pair and 3 bond pairs. As we know that the repulsion order is as follows: Lone pair-Lone pair is greater than Lone pair-Bond pair is greater than Bond pair-Bond pair. So the shape of molecule NH3 is trigonal pyramidal, where the lone pair is away from the 3 bond pairs.
5. How many orbitals are included in sp3d hybridization?
a) 5
b) 4
c) 3
d) 6
Answer: a
Clarification: The concept of mixing of atomic orbitals and formation of new hybridized atomic orbitals for the pairing of electrons through chemical bonds. Therefore sp3d hybridization included 5 orbitals namely 1 s-orbital, 3 p-orbitals, and 1 d-orbital.
6. A double bond is made up of __________
a) Two sigma bonds
b) Two pi bonds
c) One sigma and one pi bond
d) Two sigmas and one pi bond
Answer: c
Clarification: A double bond is formed chemically between two atoms that involve the bonding of four electrons. A double bond is formed with one sigma and one pi bond. The formation of molecules like ethane, oxygen involve double bonds.
7. Which of the following molecules geometry is true?
a) BrF5 – Triagonal pyramidal
b) ClF3 – T-shape
c) PCl5 – See-saw
d) SF4 – Triagonal bipyramidal
Answer: b
Clarification: The molecule ClF5 has T-shape as it 3 bonding pairs and 2 lone pairs, so it’s true. The molecules BrF5, PCl5, and SF4 have the shapes square pyramidal, trigonal bipyramidal and see-saw respectively.
8. What is the shape of water?
a) Triagonal
b) Triagonal bipyramidal
c) Bent
d) Square planar
Answer: c
Clarification: The water molecule H-O-H has an arrangement of electrons in a tetrahedral. As it contains two bond pairs and lone pairs in the form of the molecule of type AB3E2, it’s shape is bent i.e. neglecting the lone pairs.
9. The angle between two bonds in a linear molecule is _______
a) 108°
b) 180°
c) 74.5°
d) 90°
Answer: b
Clarification: A linear molecule has a hybridization sp, in which the bonds between the central atom and other atoms are separated by 180°. For example, let’s take carbon dioxide, it’s shape is given by O=C=O.