Chemical Bonding and Molecular Structure

Which one of the following statements is correct?

• Hybrid orbitals do not form σ bonds.

• Lateral overlap of p-orbitals or p- and d-orbitals produces $\mathrm{\pi }$-bonds.

• The strength of bonds follows the order-

  σ_p-p < σ_s-s < $\mathrm{\pi }$_p-p

• s-orbitals do not form σ bonds.

Which of the following is a proper match?

• A - i; B - ii; C - iv; D - iii

• A - iii; B - ii; C - iv; D - i

• A - i; B - iii; C - ii; D - iv

• A - ii; B - iv; C - i; D - iii

The correct order of increasing C-O bond length of CO, CO₂ and CO${}_3^{2-}$ is

• CO${}_3^{2-}$ < CO₂ < CO

• CO₂ < CO${}_3^{2-}$ < CO

• CO < CO${}_3^{2-}$ < CO₂

• CO < CO₂ < CO${}_3^{2-}$

Which of the following represents the Lewis structure of N₂ molecule?

Which of the following has the highest bond order?

• N₂

• O₂

• He₂

• H₂

Peroxide ion ......
(i) has five completely filled antibonding molecular orbitals
(ii) is diamagnetic
(iii) has bond order one
(iv) is isoelectronic with neon
Which one of these is correct?

• (ii) and (iii)

• (i), (ii) and (iv)

• (i), (ii) and (iii)

• (i) and (iv)

Which of the following is diamagnetic?

• H${}_2^{+}$

• He${}_2^{+}$

• O₂

• N₂

C-H bond energy is about 101 kcal/ mol for methane, ethane and other alkanes but is only 77 kcal/ mol for C-H bond of CH₃ in toluene. This is because :

• of inductive effect due to -CH₃ in toluene

• of the presence of benzene ring in toluene

• of resonance among the structures of benzyl radical in toluene

• aromaticity of toluene

Which one of the following does not have sp² hybridised carbon ?

• Acetone

• Acetic acid

• Acetonitrile

• Acetamide

The C-O-H bond angle in ethanol is nearly

• 90°

• 104°

• 120°

• 180°