Chemical Bonding and Molecular Structure

Which of the following species contains three bond pairs and one lone pair around the central atom ?

1. H2O
2. BF3
3. NH2-
4. PCl3

The pair of species with the same bond order is

1. O22-, B2
2. O2+, NO+
3. NO, CO
4. N2, O2

Which of the following structures is the most preferred and hence of lowest energy for SO3?

1. [figure]
2. [figure]
3. [figure]
4. [figure]

The pairs of species of oxygen and their magnetic behaviours are noted below. Which of the following presents the correct description?

1. O2-, O22- – Both diamagnetic
2. O2+, O2 – Both paramagnetic
3. O, O22- – Both paramagnetic
4. O+, O22- – Both paramagnetic

Which of the following has the minimum bond length ?

1. O2+
2. O2-
3. O22-
4. O2

Which of the two ions from the list given below that have the geometry that is explained by the same hybridization of orbitals, NO2-, NO3-, NH2-, NH4+, SCN-?

1. NO2- and NO3-
2. NH4+ and NO3-
3. SCN- and NH2-
4. NO2- and NH2-

The correct order of increasing bond length of C-H, C-O, C-C and C=C is

1. C-H < C=C < C-O < C-C
2. C-C < C=C < C-O < C-H
3. C-O < C-H < C-C < C=C
4. C-H < C-O < C-C < C=C

The pairs of species of oxygen and their magnetic behavior are noted below. Which of the following presents the correct description?

1. O2-, O22- - Both diamagnetic
2. O+, O22- - Both paramagnetic
3. O2+, O2 - Both paramagnetic
4. O, O22- - Both paramagnetic

Considering the state of hybridization of carbon atoms, find out the molecule among the following which is linear ?

1. CH3-CH=CH-CH3
2. CH3-C C-CH3
3. CH2=CH-CH2-C CH
4. CH3-CH2-CH2-CH3

Which of the following compounds has the lowest melting point?

1. CaCl2
2. CaBr2
3. CaI2
4. CaF2