2. • Hybridisation of Acetylene is _____________
a) sp
b) sp2
c) sp3
d) dsp2
• a) sp
Explanation: The Acetylene molecule is C2H2. It is
sp hybridised.
3. • Shape of PCl5 molecule is _____________
a) Tigonal Planar
b) Linear
c) Trigonal bipyramidal
d) Tetrahedral
• c) Trigonal bipyramidal
Explanation: PCl5 is trigonal bipyramidal with
its bond angle equal to 1200 and 900.
4. • Predict the shape of the H2O compound based
upon concepts of hybridisation.
a) Tetrahedral
b) Angular or bent structure
c) Trigonal Planar
d) Pyramidal
• b) Angular or bent structure
Explanation: The water molecule has angular or
bent structure due to the presence of two lone
pairs which repels strongly.
5. • Which of the following is an example of
sp3d2 hybridised molecule?
a) HCHO
b) ClO4
–
c) SF6
d) PF5
• c) SF6
Explanation: The SF6 molecule is sp3d2 hybridised
and the shape is regular octahedron.
6. • Due to unsymmetrical structure, the molecules having
sp3d hybridisation are ____________
a) more stable and more reactive
b) less stable and more reactive
c) more stable and less reactive
d) less stable and less reactive
• b) less stable and more reactive
Explanation: In sp3d hybridisation, due to its
unsymmetrical structure the molecules are in the
shape of trigonal bipyramidal which is less stable and
more reactive.
7. • Number of chlorine atoms which form equatorial
bonds in PCl5 molecule are ____________
a) 1
b) 2
c) 3
d) 4
• c) 3
Explanation: In PCl5 molecule, three chlorine atoms
which lie at an angle of 1200 in the same plane forms
equatorial bonds and the other two atoms forms axial
bonds at an angle of 900.
8. • The bond angles in sp3d2 hybridisation is
____________
a) 900
b) 1200
c) 109.50
d) 1800
• a) 900
Explanation: All the bond angles are equal in
sp3d2 hybridisation i.e., 900
9. • The hybridisation of BeF3- is _____________
a) sp3
b) sp
c) sp2
d) d2sp3
• c) sp2
Explanation: The hybridisation of BeF3 is sp2 and
it is trigonal planar.
10. • All the hybridised orbital are not equal in
energy and shape.
a) True
b) False
• b) False
Explanation: All the hybridised orbital are
equal in energy and shape. They are similar to
each other and possess equal energy levels.
11. • The percentage p-character in sp3 hybridisation is
____________
a) 25%
b) 50%
c) 75%
d) 66.67%
• c) 75%
Explanation: In sp3 hybridisation, s-character is
25% and p-character is 75%.
12. • Valence Bond Theory was developed in the year?
a) 1916
b) 1927
c) 1930
d) 1932
• b) 1927
Explanation: The Valence Bond Theory was
developed in 1927 by Heitler and London.
13. • According to VBT, the formation of a stable bond
requires _____________
a) The electrons should have opposite spins
b) The two atoms should be close to each other
c) The greater overlapping of the electron clouds
d) All of the mentioned
• d) All of the mentioned
Explanation: According to VBT, when two atoms come
closer to each other with opposite electron spins, due
to mutual rearrangements (or overlapping) of their
electron clouds, energy changes are produced.
14. • The s-orbital does not show preference to any direction
because _____________
a) It is the smallest orbital
b) It is present in every atom
c) It is spherically symmetric
d) It is the first orbital
• c) It is spherically symmetric
Explanation: The s-orbital is spherically symmetric in
shape so it does not show preference to any direction.
It is the same from all the directions.
15. • The p-orbital is in the shape of a _____________
a) Sphere
b) Dumbbell
c) Pear-shaped lobe
d) None of the mentioned
• b) Dumbbell
Explanation: The p-orbital is in the shape of a
Dumbbell. It has 2 lobes that are pointing in
opposite directions.
16. • The Valence Bond Theory does not explain the
paramagnetic nature of oxygen molecule.
a) True
b) False
• a) True
Explanation: Oxygen molecule is paramagnetic in
nature, although it does not contain unpaired
electrons which is not explained in VBT.
17. • According to VBT, the direction of a bond which is formed
due to overlapping will be _____________
a) In the same direction in which orbitals are concentrated
b) In the opposite direction in which orbitals are
concentrated
c) Perpendicular to the direction in which orbitals are
concentrated
d) None of the mentioned
• a) In the same direction in which orbitals are concentrated
Explanation: The direction of the bond formed will be in
that direction in which the orbitals are concentrated. For
Example: When two px orbitals overlap, the bond is formed
along the x-axis.
18. • Which orbital would form a more stronger bond if
both of them have identical stability?
a) The one which is less directionally concentrated
b) The one which is more directionally concentrated
c) Both will be equally strong
d) It differs from atom to atom
• b) The one which is more directionally concentrated
Explanation: When the two orbitals have identical
stability or energy, the one which is more directionally
concentrated would form a stronger bond.
19. • The formation of odd electron molecules such as
H2
+, NO, O3 is also explained in VBT.
a) True
b) False
• b) False
Explanation: The Valence Bond Theory does not
explain the formation of odd electron molecules
such as H2
+, NO, O3 etc, where no electron pairing
takes place.
20. • 1. The bond enthalpy of ___________ molecule is 435.8 kJ
mol-1.
a) Hydrogen
b) Oxygen
c) Nitrogen
d) Helium
• a) Hydrogen
Explanation: The amount of energy that is required to
break a chemical bond in a molecule into individual atoms
is known as bond enthalpy. 435.8 kJ mol-1 is required to
dissociate a hydrogen molecule into two hydrogen atoms.
21. • The strength of covalent ___________ extent of
overlapping of orbitals.
a) may be or may not be related
b) is independent on
c) is dependent on
d) is not related to
• c) is dependent on
Explanation: As per the concept of valence bond theory,
the partial merging of atomic orbitals id knowns as
overlapping. The extent of overlapping is directly
proportional to the strength of the covalent bond, i.e. it is
dependent.
22. • Which type of bond is present between hydrogens in
hydrogen molecule?
a) Sigma bond
b) Pi bond
c) Ionic bond
d) Metallic bond
• a) Sigma bond
Explanation: The head-on or end to end type of overlapping
is present in sigma bond. A sigma bond is a type of covalent
bond. It may also be called an axial overlap. In case of the
hydrogen molecule, its s-s overlapping.
23. • The pi-bond involves __________
a) axial overlapping
b) side-wise overlapping
c) end to end type of overlapping
d) head-on overlapping
• b) side-wise overlapping
Explanation: A pi-bond is a type of covalent bond in
which the internuclear axes of the atoms are parallel to
each other and for side-wise overlapping. The bond
formed here is perpendicular to the internuclear axes.
24. • A pi bond is stronger than a sigma bond.
a) True
b) False
• b) False
Explanation: A sigma bond is always stronger
than the pi bond. As we know that the bond
strength is decided by the extent of orbital’s
overlapping. The extent of overlapping is more in
sigma bond than in a pi-bond.
25. • A __________ overlap doesn’t result in the formation of a
bond.
a) positive
b) negative
c) zero
d) rational
• c) zero
Explanation: Zero overlap means that the orbitals don’t
overlap at all. When there is no overlapping the bond
formation doesn’t occur. As we all know that the extent of
overlapping is dependent on the strength of the bond.
26. • A positive overlap is same as ________
a) out-phase overlap
b) negative overlap
c) zero overlap
d) in-phase overlap
• d) in-phase overlap
Explanation: A positive overlap results in bond
formation. When 2 p-orbitals are in phase, both the
positive lobes overlap, thus creating a positive overlap
and result in the bond formation, thus it is called in-
phase overlap.
27. • Valence bond theory explains the overlapping of
atomic orbitals.
a) True
b) False
• a) True
Explanation: Valence bond theory was initially
introduced by London and Heitler and was developed
by Pauling and others. It’s a chemical bonding theory
that explains the overlapping the atomic orbitals in
order to form chemical bonds between atoms.
28. • Which of the following is not a homonuclear diatomic
molecule?
a) H2
b) N2
c) O2
d) HCl
• d) HCl
Explanation: The molecule that is formed from the same
element is known as a homonuclear molecule and the
molecule that is made up of 2 atoms is called a diatomic
molecule. But HCl is not a homonuclear diatomic molecule
as it has different atoms.
