1. Pauling scale is based on which energy?
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Correct Answer
Bond Dissociation Energy
Detailed Explanation
The Pauling electronegativity scale is based on
bond energies / bond dissociation energies.
Pauling compared the strength of a heteronuclear bond such as:
A—B
with the corresponding homonuclear bonds:
A—A and B—B
If the A—B bond is stronger than expected from the A—A and B—B bond
energies, the extra bond strength is attributed to the difference in
electronegativity between A and B.
Pauling Relationship
The electronegativity difference is related to bond dissociation energies.
In a simplified form:
Δχ = χA − χB
The difference is estimated from the excess bond energy of the heteronuclear
bond.
A commonly used relation is:
|χA − χB|
≈ 0.102√[D(A−B) − √(D(A−A)D(B−B))]
when bond energies D are expressed in kJ mol−1.
Example
Suppose the A—B bond is unusually strong compared with A—A and B—B.
This indicates that the bonding electrons are attracted unequally toward one
atom.
Therefore:
Greater bond-energy difference → Greater electronegativity difference
This is the basic idea behind the Pauling scale.
Do Not Confuse the Scales
Pauling: Based on bond dissociation energies.
Mulliken: Based on ionization energy and electron affinity.
Mulliken: Based on ionization energy and electron affinity.
χM = ½(I + A)
Allred–Rochow: Based on effective nuclear charge and
covalent radius.
Pauling → Bond Energy
Mulliken → I.E. + E.A.
Mulliken → I.E. + E.A.
JEE / NEET Shortcut
Remember:
Pauling = Bond Dissociation Energy
If an MCQ asks:
“Pauling electronegativity scale is based on?”
the direct answer is:
Bond dissociation energy
30 Related MCQs with Solutions
1. Pauling's electronegativity scale is based on:
A. Ionization energy
B. Electron affinity
C. Bond dissociation energy
D. Atomic radius
Answer: C. Bond dissociation energy
2. Pauling compared which bonds to estimate electronegativity difference?
A. Only ionic bonds
B. Homonuclear and heteronuclear bonds
C. Metallic bonds only
D. Hydrogen bonds only
Answer: B
3. Bond dissociation energy refers to energy required to:
A. Form an atom
B. Break a bond homolytically in the gas phase
C. Remove a neutron
D. Add a proton
Answer: B
4. Which scale uses ionization energy and electron affinity?
A. Pauling
B. Mulliken
C. Allred–Rochow
D. Metallic scale
Answer: B. Mulliken
5. The Pauling scale measures:
A. Atomic mass
B. Relative electronegativity
C. Ionization energy directly
D. Electron affinity directly
Answer: B
6. A stronger-than-expected A—B bond suggests:
A. Zero electronegativity difference
B. Electronegativity difference between A and B
C. No covalent character
D. Metallic bonding
Answer: B
7. Pauling's concept is associated mainly with:
A. Chemical bond energies
B. Atomic mass
C. Nuclear radius
D. Density
Answer: A
8. Which bond is heteronuclear?
A. H—H
B. Cl—Cl
C. H—Cl
D. O—O
Answer: C. H—Cl
9. Which bonds are homonuclear?
A. H—Cl
B. H—F
C. Cl—Cl
D. H—O
Answer: C. Cl—Cl
10. Greater electronegativity difference generally causes:
A. Greater bond polarity
B. Lower bond polarity
C. No polarity
D. Metallic bonding only
Answer: A
11. The Pauling scale is named after:
A. Linus Pauling
B. Robert Mulliken
C. Alfred Werner
D. Henry Moseley
Answer: A. Linus Pauling
12. Which scale is based on bond energy differences?
A. Pauling
B. Mulliken
C. Allred–Rochow
D. None
Answer: A
13. The unit commonly used for bond dissociation energy is:
A. kJ mol⁻¹
B. mol L⁻¹
C. atm
D. kg
Answer: A
14. Which quantity is NOT directly used in the Mulliken definition?
A. Ionization energy
B. Electron affinity
C. Bond dissociation energy
D. Both A and B are used
Answer: C
15. Which scale is represented by χ = ½(I + A)?
A. Pauling
B. Mulliken
C. Allred–Rochow
D. Allen
Answer: B. Mulliken
16. If the A—B bond has greater energy than expected, this is called:
A. Excess bond strength
B. Nuclear shielding
C. Ionization energy
D. Electron affinity
Answer: A
17. The Pauling scale is primarily a:
A. Relative scale
B. Mass scale
C. Radius scale
D. Pressure scale
Answer: A
18. Which scale is directly associated with electron affinity and ionization energy?
A. Pauling
B. Mulliken
C. Allred–Rochow
D. None
Answer: B
19. A—A represents a:
A. Heteronuclear bond
B. Homonuclear bond
C. Ionic bond
D. Metallic bond
Answer: B
20. A—B represents a:
A. Homonuclear bond
B. Heteronuclear bond
C. Metallic bond
D. Coordinate bond necessarily
Answer: B
21. Pauling electronegativity is useful for predicting:
A. Bond polarity
B. Atomic mass
C. Nuclear stability only
D. Melting point only
Answer: A
22. Greater difference in electronegativity generally means:
A. More polar bond
B. Less polar bond
C. No charge separation
D. Pure metallic bond
Answer: A
23. Which is the correct matching?
A. Pauling — bond energies
B. Mulliken — atomic radius only
C. Allred–Rochow — electron affinity only
D. Pauling — neutron number
Answer: A
24. Which quantity is compared for A—B, A—A and B—B bonds in Pauling's approach?
A. Bond dissociation energy
B. Atomic mass
C. Density
D. Ionization potential only
Answer: A
25. Pauling's scale is especially useful for comparing:
A. Electronegativity of elements
B. Atomic masses
C. Nuclear masses
D. Densities
Answer: A
26. Which statement is correct?
A. Pauling scale uses bond energies
B. Mulliken scale uses bond energies only
C. Pauling scale uses neutron number
D. Pauling scale ignores chemical bonds
Answer: A
27. If electronegativity difference increases, bond polarity generally:
A. Increases
B. Decreases
C. Becomes zero
D. Is unrelated
Answer: A
28. Which is the best one-line memory trick?
A. Pauling → Bond Energy
B. Mulliken → Bond Energy
C. Pauling → Atomic Mass
D. Pauling → Nuclear Radius
Answer: A
29. The Pauling scale is fundamentally based on:
A. Difference in bond energies
B. Difference in atomic masses
C. Difference in neutron numbers
D. Difference in melting points
Answer: A
30. The correct answer to the original question is:
A. Ionization energy
B. Electron affinity
C. Bond dissociation energy
D. Atomic radius
Answer: C. Bond dissociation energy
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