Chemistry Question Bank on “Molecular Structure – Hybridisation”.
1. Who introduced the concept of hybridization?
a) Pauling
b) London
c) Sidgwick
d) Alexander
Answer: a
Clarification: In order to explain the bonding and shapes of every polyatomic atomic molecule like methane, carbon tetrachloride, water, boron trifluoride, etc, Pauling put-forth the concept of hybridization.
2. The phenomenon of forming completely new atomic orbitals by intermixing them is known as ___________
a) Allocation
b) Hybridization
c) Chemical bond formation
d) Electron configuration
Answer: b
Clarification: The exact meaning of hybridization is the intermixing of different orbitals in order to form a new set of equivalent orbitals otherwise known as hybridized orbitals. These hybrid orbitals are used in bond formation.
3. The orbitals that are resulted from sp hybridization have _______% s-character and ________% p-character.
a) 25, 75
b) 75, 25
c) 20, 80
d) 50, 50
Answer: d
Clarification: When one s-orbital and p-orbital undergo hybridization, 2 sp orbitals are formed. One sp-orbital has 50% s-character and 50% p-character. They possess linear geometry and it’s also called diagonal hybridization.
4. What type of hybridization does a BCl3 molecule undergo?
a) sp
b) sp2
c) sp3
d) sp3d
Answer: b
Clarification: In the BCl3 molecule, one s-orbital and two p-orbitals intermix and form three equivalent hybrid orbits. Therefore it undergoes sp2 hybridization and forms trigonal planar shape, like B in the center and Cl in the 3 corners.
5. What is the bond angle of H-C-H in methane molecule?
a) 104.5°
b) 109.5°
c) 108°
d) 120°
Answer: b
Clarification: The molecule of methane i.e. CH4 had undergone sp3 hybridization (1 s-orbital and 3 p-orbitals combine to give 4 sp3 orbitals). It exhibits tetrahedral geometry. In tetrahedral geometry, the angle between the bonds of corner atoms and the central atom is 109.5°.
6. What do you think is the number of sigma bonds in an ethene molecule?
a) 6
b) 7
c) 4
d) 5
Answer: d
Clarification: The formula of ethene molecule is C2H4. There is one sigma bond between two carbon atoms and 2 sigma bonds between each of the carbon and the hydrogens. So in total, it’s five (one pi-bond is present between the 2 carbon atoms).
7. Mention the types of orbitals that undergo hybridization in order to get octahedral geometry?
a) s-orbital only
b) s-orbital and p-orbital
c) s-orbital, p-orbital, and d-orbital
d) d-orbital and p-orbital
Answer: c
Clarification: Octahedral geometry is possible when the atomic orbitals under undergoing sp3d2 or d2sp3 hydration only. So it involves one s-orbital, three p-orbitals, and two d-orbitals. An example of this is SF6.
8. What is the geometry of PCl5 molecule?
a) Square pyramidal
b) V-shape
c) Trigonal bipyramidal
d) Tetrahedral
Answer: c
Clarification: As the PCl5 molecule undergoes sp3d hybridization, it posses the geometry the trigonal bipyramidal. In the shape, the central atom is Phosphorous and the atoms at the five corners are Chlorine.
9. The orbitals formed after hybridization have equal energy.
a) True
b) False
Answer: a
Clarification: The hybridization is the intermixing of different orbitals in order to form a new set of equivalent orbitals otherwise known as hybrid orbitals. All the hybrid orbitals those have undergone the same hybridization have the same amount of energy.
10. Which of the following statement is true regarding hybrid orbitals?
a) The amount of orbitals formed after the hybridization is not equal to the number of orbitals before hybridization
b) The hybrid orbitals don’t have equal energy
c) They can form more stable bonds than the pure orbitals
d) Hybridization doesn’t indicate geometry
Answer: c
Clarification: The true statements of the incorrect ones are the number of orbitals formed after the hybridization is equal to the number of orbitals before hybridization, the hybrid orbitals have equal energy and the hybridization indicates geometry.
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