Chemical Bonding and Molecular Structure

Q1. Kossel and Lewis approach was based on the:

1. Reactivity of elements.
2. Inertness of noble gases.
3. Reactivity of metals.
4. Inertness of non-metals.

Q2. Which of the following methods can be used for the formation of bond in homonuclear diatomic hydrogen 1
molecule?

1. Non-linear combination of atomic orbitals.
2. Linear combination of atomic orbitals.
3. Linear combination of molecular orbitals.
4. None of the above.

Q3. The shape of a molecule depends on:

1. Number of bonded valence electron pairs.
2. Number of non-bonded valence electron pairs.
3. All the electrons.
4. ‘a’ and ‘b’ above.

Q4. The decreasing order of the repulsive interaction of electron pairs is (Here, lp = lone pair, bp = bond pair):

1. lp-lp > lp-bp > bp-bp.
2. lp-bp > lp-lp > bp-bp.
3. lp-lp > bp-bp > lp-bp.
4. bp-bp > lp-lp > lp-bp.

Q5. The product of the magnitude of the charge and the distance between the centres of positive and negative
charge is called:

1. Charge ratio.
2. Dipole moment.
3. Current flow.
4. Magnetic moment.

Q6. In case of bonding molecular orbital the electron density is located:

1. Away from the space between nuclei of the bonded atom.
2. Between the nuclei of the bonded atoms.
3. In the outer shell.
4. In the inner orbital.

Q7. The valence bond theory explains the shape, the formation and directional properties of bonds in polyatomic
molecules like CH , NH and H O etc, in terms of:

1. Overlapping of atomic orbitals.
2. Hybridisation of atomic orbitals.
3. Both (a) and (b).
4. None of the above.

Q8. VBT theory is based on the:

1. Knowledge of atomic orbitals and electronic configuration of elements.
2. Overlapping criteria and the hybridisation of atomic orbitals.
3. The principles of variation and superposition.
4. All of the above.

Q9. The bond formed, as a result of the electrostatic attraction between the positive and negative ions was termed
as:

1. Electrovalent bond.
2. Covalent bond.
3. Coordinate bond.
4. None of these.

Q10. The amount of energy required to break one mole of bonds of a particular type between two atoms in a gaseous
state is called:

1. Bond enthalpy.
2. Bond angle.
3. Bond order.
4. None of these.

Q23. Lewis approach helps in writing the structure of molecules but it fails to explain:

1. The formation of chemical bond.
2. The reason for the difference in bond dissociation enthalpies and bond lengths in molecule like H , F etc.
3. The idea about the shapes of polyatomic molecules.
4. All of the above.

Q11. The structure which represents the molecular structure more accurately is called:

1. Resonance hybrid.
2. Canonical structure.
3. Resonating structure.
4. None of these.

Q12. If internuclear axis is taken to be in z-direction then, which of the following orbital does form bond?
Choose the correct option:

1. P_x orbitals.
2. P_y orbitals.
3. P_z orbitals.
4. All of these.

Q13. Which of the following statements are correct about CO₃^2-?

1. The hybridization of central atom is sp3 .
2. Its resonance structure has one C – O single bond and two C = O double bonds.
3. The average formal charge on each oxygen atom is 0.67 units.
4. All C – O bond lengths are equal.

Q14. The formation of hydrogen molecule takes place when:

1. The energy state is minimum.
2. Two hydrogen atomic orbitals undergo large extent of overlapping.
3. Both (a) and (b).
4. None of the above.

Q15. Ionic bonds will be formed more easily between elements with comparatively:

1. Low ionisation enthalpy and high electron affinity.
2. High ionisation enthalpy and high electron affinity.
3. Low ionisation enthalpy and low electron affinity.
4. High ionisation enthalpy and low electron affinity.

Q16. The group valence of the element is generally equal to the:

1. Number of dots in Lewis symbol.
2. Eight minus the number of dots.
3. Valence electrons.
4. Any of the above may possible.

Q17. expressed as wave function can represent:

1. Probability of an electron.
2. Amplitude of the electron waves.
3. Electron wave function.
4. Both (a) and (c).

Q18. Which of the following angle corresponds to sp hybridisation?

1. 90º
2. 120°
3. 180°
4. 109°

Q19. Lewis has pictured the atom in terms of kernel and the outermost shell that could accommodate a maximum of:

1. 6 electrons.
2. 10 electrons.
3. 8 electrons.
4. 2 electrons.

Q20. The molecular formula of the compound formed from B and C will be:

1. BC
2. B₂C
3. BC₂
4. BC₃

Q21. Which of the following molecule does not show hydrogen bonding?

1. HF
2. H₂O
3. NH₃
4. H S

Q22. The condition to form a molecular orbital from atomic orbitals is:

1. Atomic orbitals must have comparable energies and of proper symmetry.
2. Only atomic orbitals must be in proper symmetry.
3. Only atomic orbitals must be of comparable energies.
4. None of the above.

Q23. Which of the following molecules is expected to be diamagnetic?

1. S₂
2. B₂
3. N₂
4. O₂

Q24. In which of the following molecules molecular orbital is filled after and molecular orbitals?

1. O₂
2. Ne₂
3. N₂
4. F₂

Q25. In the formation of bonding molecular orbital, the two electrons waves of the bonding atoms reinforce each
other due to:

1. Constructive interference.
2. Destructive interference.
3. Both (a) and (b).
4. None of the above.

Q26. According to Pauling, the atomic orbitals combine to form new set of equivalent atomic orbitals known as:

1. Molecular orbitals.
2. Hybrid orbitals.
3. Pure orbitals.
4. None of these.

Q27. The electron probability distribution around a group of nuclei in a molecule is given by:

1. Atomic orbital.
2. Molecular orbital.
3. Antibonding molecular orbital.
4. None of the above.

Q28. Which of the following statements are not correct?

1. NaCl being an ionic compound is a good conductor of electricity in the solid state.
2. In canonical structures there is a difference in the arrangement of atoms.
3. Hybrid orbitals form stronger bonds than pure orbitals.
4. Vsepr theory can explain the square planar geometry of XeF₄

Q29. Which of the following compounds shows the presence of intramolecular H-bond?

1. H₂O₂
2. HCN
3. Cellulose
4. Conc. Acetic acid

Q30. Which theory can be best understood by considering the formation of the chlorine molecule, Cl₂ ?

1. Lewis theory.
2. Langmuir theory.
3. Lewis-Langmuir theory.
4. Kossel-Lewis theory.