Chemical Bonding and Molecular Structure

The electronegativity difference between N and F is greater than that between N and H yet the dipole moment of NH3 (1.5 D) is larger than that of NF3 (0.2 D). This is because

1. in NH3 the atomic dipole and bond dipole are in the opposite directions whereas in NF3 these are in the same direction
2. in NH3 as well as in NF3 the atomic dipole and bond dipole are in the same direction
3. in NH3 the atomic dipole and bond dipole are in the same direction whereas in NF3 these are in opposite directions
4. in NH3 as well as in NF3 the atomic dipole and bond dipole are in opposite directions.

In which of the following molecules are all the bonds not equal?

1. NF3
2. ClF3
3. BF3
4. AlF3

Which of the following molecules has trigonal planar geometry?

1. BF3
2. NH3
3. PCl3
4. IF3

The correct order in which the O-O bond length increases in the following is

1. O2 < H2O2 < O3
2. O3 < H2O2 < O2
3. H2O2 < O2 < O3
4. O2 < O3 < H2O2

The correct sequence of increasing covalent character is represented by

1. LiCl < NaCl < BeCl2
2. BeCl2 < LiCl < NaCl
3. NaCl < LiCl < BeCl2
4. BeCl2 < NaCl < LiCl

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.