Bonding
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Question 1
Which compound contains ionic bonds?
Ethanoic acid,
CH3COOH
Dichloroethane,
CH2Cl2
Magnesium chloride,
MgCl2
Silicon
tetrabromide,SiBr4
Wrong Answer!
Magnesium is a metal and chlorine is a non-metal.
Typically, a metal and non-metal react to form an ionic
compound.
Question 2
When CH4 , NH3 and H2O are arranged in order of
dereasing bond angle, what is the correct order?
CH4 , NH3 , H2O
NH3 , H2O , CH4
NH3 , CH4 , H2O
H2O , NH3 , CH4
Wrong Answer!
All the molecules are based upon tetrahedral
arrangement of 4 regions of high electron density.
However, lone pairs cause more repulsion than bonding
pairs. The oxygen in H2O is surrounded by 2 lone pairs
(max repulsion), the nitrogen atom in NH3 contains 1
lone pair, but the carbon in CH4 has no lone pairs ( least
repulsion)
Question 3
In which of the following is there at least one
double bond?
I. O2
II. CO2
III.C2F2
I only
III only
II and III only
I , II and III
Wrong Answer!
The oxygen molecule (O=O) contains 1 double bond, the
carbon dioxide (O=C=O) contains 2 double bonds and
thetetrafluoroethane molecule contains 1 double bond
Question 4
Why is the boiling point of ethane greater than that
of neon?
The ethane molecule is
polar.
Hydrogen bonds form
between ethane molecules but
not present in liquid neon.
More electrons are
present in ethane than
in neon.
A molecule of ethane has a
greater mass than a neon
atom.
Wrong Answer!
Both ethane and neon are non-polar. Hence, the
predominant intermolecular and inter-atomic forces are
van der Waals’ forces whose size depends on the
number of electrons present in the atoms or molecules. A
greater number of electrons in the ethane molecule
results in a stronger temporary dipole which makes
neighbouring molecules or atoms attract each other more
strongly. This means more heat is reqiured to overcome
the intermolecular or inter-atomic forces in ethane
molecules, resulting higher boiling point.
Question 5
What is the formula for the compound formed by
strontium and nitrogen?
Sr3N2
Sr2N3
Sr2N
SrN
Wrong Answer!
Strontium form Sr2+ and nitrogen forms N3- .Hence, the
formula of strontium nitride is Sr3N2
Question 6
A solid has a melting point 14400C. It conducts
heat and electricity. It does not dissolve in water
or in organic solvents. The bond between the
particle is most likely to be
covalent
ionic
dipole-dipole
metallic
Wrong Answer!
Generally, metals have high melting points, contain
delocalized electrons, insoluble in water and excellent
conductors.
Question 7
Which is the best description of metallic bonding?
The attraction between
positve and negative
ions.
The attraction between the
The attraction between
protons and electrons .
The attraction between
nuclei and shared electron
pairs.
nuclei of positive ions and
delocalized valene electrons.
Wrong Answer!
D is a description of covalent bonding. A is a description
of ionic bonding.
Question 8
Which compound is the most soluble in water?
ethane
propane
propan-1-ol
hexan-1-ol
Wrong Answer!
Ethane and propane are hydrocarbons and hence unable
to form hydrogen bonds with water. Propan-1-ol and
hexan-1-ol are both alcohols and contan hydroxyl group
–OH, capable of forming hydrogen bonds with water
molecules. However, propan-1-ol is more soluble since
its hydrocarbon chain is smaller, 3 C atoms compared to
6 in hexan-1-ol .
Question 9
Which is not present in C2H5OC2H5 in the liquid
state?
covalent bonding
van der Waals’ force
dipole-dipole
attractions
hydrogen bonding
Wrong Answer!
All of the hydrogen atoms are attached to C atoms and
hence are unable to engage in hydrogen bonding.
Question 10
The angle between the two carbon-carbon bonds
in CH3CHCF2 is closest to
1800
1200
1090
900
Wrong Answer!
The molecule has a C=C bond. There are 3 regions of
high electron density around the 2 carbon atoms. Hence,
the molecule is trigonal planar and has bond angles of
1200.
Question 11
The molar masses of C2H6, CH3OH and CH3F are
similar. How do their boiling points compare?
C2H6<CH3OH<CH3F
CH3F<CH3OH<C2H6
CH3OH<CH3F<C2H6
C2H6<CH3F<CH3OH
Wrong Answer!
Ethane, C2H6 has a lower boiling point due to the
presence of van der Waals forces of attraction – weakest
of the 3 intermolecular forces. Fluoromethane, CH3F has
an intermediate boiling point owing to the presence of
dipole-dipole forces. Methanol, CH3OH has the highest
boiling point owing to the presence of hydrogen bonding.
Question 12
Which of the following molecules is a triangular
planar?
NCl3
C2H4
C3H6
SF6
Wrong Answer!
C2H4 has a trigonal planar arrangement around the 2
carbon atoms.
Question 13
Which intermolecular forces exist in dry ice,
CO2(s)?
dipole-dipole
interactions
covalent bonds
van der Waals’
forces
hydrogen bonds
Wrong Answer!
CO2 is a non-polar molecule due to its linear shape. The
2 dipoles cancel each other out. Hence, the forces
operating in the soild are van der Waals’ forces.
Question 14
In general, the strengths of the following
intermolecular forces and bonds increase in the
order
covalent bonds, hydrogen
bonds, van der Waals
forces
van der Waals forces
hydrogen bonds,
covalent bonds
covalent bonds, van der
Waals forces, hydrogen
bonds
hydrogen bonds,
covalent bonds, van der
Waals forces
Wrong Answer!
The relative order of strength is van der Waals’ forces,
hydrogen bonds, covalent bonds
Question 15
Given the following electronegativity values:
H: 2.1
N: 3.0
O: 3.5
F:4.0
which bond has the greatest polarity?
O-H in H2O
N-O in NO2
N-F in NF3
N-H in NH3
Wrong Answer!
The largest difference in electronegativity value is from O
and H atoms.
Question 16
Which one of the species has a triangular
pyramidal geometry?
BCl3
NCl3
H2Se
C2H3
Wrong Answer!
The nitrogen atom in NCl3 is surrounded by 3 bonding
pairs and 1 lone pair.
Question 17
In which of the following substances would
hydrogen bonding be expected to occur?
I. C2H6
II. CH3CH2COOH
III.CH3COCH3
II only
I and III only
II and III only
I, II and III
Wrong Answer!
A hydrogen bond would expect to occur in
CH3CH2COOH since it contains hydrogen bonded
directly to oxygen. The OH group is able to engage in
hydrogen bonding. In the other 2 compounds, the
hydrogen is bonded to C.
Question 18
When the Lewis structure for HCOOCH3 is drawn,
how many bonds and how many lone pairs of
electrons are present?
5 and 5
7 and 4
8 and 4
7 and 5
Wrong Answer!
Each oxygen atom has 2 lone pairs, so there are 8
bonds. 4 x C-H, 2 C-O, 1 X C=O
Congratulations!