Chemical Bonding and Molecular State NDA Questions

NDA Chemistry

Chemical Bonding and Molecular State MCQ Questions


13.
Formal charge is a useful tool for identifying the most stable Lewis structure, which is generally the one with formal charges:
A.
Closest to zero
B.
All negative
C.
As large as possible
D.
All positive
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ANSWER :
A. Closest to zero
14.
The number of covalent bonds an atom can form, as dictated by the octet rule, is termed its:
A.
Atomicity
B.
Covalency
C.
Electronegativity
D.
Oxidation state
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ANSWER :
B. Covalency
15.
Owing to resonance, the actual bond order of each Cā€“O bond in the carbonate ion (CO3^2āˆ’) is approximately:
A.
1.5
B.
2.0
C.
1.0
D.
1.33 (4/3)
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ANSWER :
D. 1.33 (4/3)
16.
The bonding in ozone (O3), where a single Lewis structure cannot fully explain equal bond lengths, is best described using the concept of:
A.
Hybridisation alone
B.
Metallic bonding
C.
Ionic bonding
D.
Resonance
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ANSWER :
D. Resonance
17.
The sulfate ion (SO4^2āˆ’), in which all four Sā€“O bonds are experimentally equivalent, is best explained using the Lewis-structure concept of:
A.
Resonance
B.
Duplet rule
C.
Octet violation
D.
Formal charge alone
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ANSWER :
A. Resonance
18.
When drawing the Lewis structure of a polyatomic species, the atom that is generally placed at the centre is the one that is:
A.
Always hydrogen
B.
The least electronegative (most electropositive) atom, other than hydrogen
C.
The most electronegative atom
D.
Always oxygen
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ANSWER :
B. The least electronegative (most electropositive) atom, other than hydrogen