Which of the following is isoelectronic with CO₂?

• NO₂

• NO

• N₂O

• N₂O₄

All bond angles are exactly equal to 109° 28' in:

• methyl chloride

• iodoform

• chloroform

• carbon tetrachloride

The molecular shapes of SF₄, CF₄ and XeF₄ are

• different with 1, 0 and 2 lone pairs of electrons on the central atom, respectively

• different with 0, 1 and 2 lone pairs of electrons on the central atom, respectively

• the same with 1, 1 and 1 lone pair of electrons on the central atoms, respectively

• the same with 2, 0 and 1 lone pairs of electrons on the central atom, respectively

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

• Acetone

• Acetic acid

• Acetonitrile

• Acetamide

The bond order of N${}_2^{+}$ is

• 1.5

• 3.0

• 2.5

• 2.0

Among the following, the pair in which the two species are not isostructural, is

• SiF₄ and SF₄

• IO${}_3^{-}$ and XeO₃

• BH${}_4^{-} \mathrm{and} {\mathrm{NH}}_4^{+}$

• PF${}_6^{-}$ and SF₆

587.

The helical structure of protein is stabilized by

• dipeptide bond

• hydrogen bonds

• ether bonds

• peptide bonds

The dipole moment of HBr is 1.6 × 10^-30 cm and inter-atomic spacing is 1 Å. The % ionic character of HBr is

• 7

• 10

• 15

• 27

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

• 90°

• 104°

• 120°

• 180°

The molecule having zero dipole moment is

• CH₂Cl₂

• BF₃

• NF₃

• ClF₃