Chemical Bonding and Molecular Structure

Which of the following would have a permanent dipole moment?

1. SiF4
2. SF4
3. XeF4
4. BF3

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

1. SiF4 and SF4
2. IO3- and XeO3
3. BH4- and NH4+
4. PF6- and SF6

In a regular octahedral molecule, MX6, the number of X - M - X bonds at 180 is

1. three
2. two
3. six
4. four

H2O is dipolar, whereas BeF2 is not. It is because

1. the electronegativity of F is greater than that of O
2. H2O involves hydrogen bonding whereas BeF2 is a discrete molecule
3. H2O is linear and BeF2 is angular
4. H2O is angular and BeF2 is linear.

In BrF3 molecule, the lone pairs occupy equatorial positions to minimize

1. lone pair - bond pair repulsion only
2. bond pair - bond pair repulsion only
3. lone pair - lone pair repulsion and lone pair - bond pair repulsion
4. lone pair - lone pair repulsion only.

Which one of the following statements is not correct for sigma- and pi- bonds formed between two carbon atoms?

1. sigma-bond is stronger than a pi-bond.
2. Bond energies of sigma- and pi-bonds are of the order of 264 kJ/mol and 347 kJ/mol, respectively
3. Free rotation of atoms about a sigma-bond is allowed but not in case of a pi-bond.
4. Sigma-bond determines the direction between carbon atoms but a pi-bond has no primary effect in this regard.

Which of the following has p - d bonding?

1. NO3-
2. SO32-
3. BO33-
4. CO32-

In NO3- ion number of bond pair and lone pair of electrons on nitrogen atom are

1. 2, 2
2. 3, 1
3. 1, 3
4. 4, 0

Main axis of a diatomic molecule is z, atomic orbitals px and py overlap to form which of the following orbitals.

1. molecular orbital
2. molecular orbital
3. molecular orbital
4. No bond will form

Which of the following two are isostructural?

1. XeF2, IF2-
2. NH3, BF3
3. CO32-, SO32-
4. PCl5, ICl5