Chemical Bonding and Molecular Structure

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

In which of the following bond angle is maximum ?

1. NH3
2. NH4+
3. PCl3
4. SCl2

In X-H Y, X and Y both are electronegative elements. Then

1. electron density on X will increase and on H will decrease
2. in both electron density will increase
3. in both electron density will decrease
4. on X electron density will decrease and on H will increase.

d - p bond present in

1. CO32-
2. PO43-
3. NO3-
4. NO2-

Right order of dissociation energy N2 and N2+ is

1. N2 > N2+
2. N2 = N2+
3. N2+ > N2
4. none

Which species does not exhibit paramagnetism?

1. N2+
2. O2-
3. CO
4. NO