Which one of the following molecules has the least dipole moment?

• H₂O

• BeF₂

• NH₃

• NF₃

Dipole-dipole interaction energy between polar molecules in solids depends on the radius of the molecule (r) and it is directly proportional to

• (1/r³)

• (1/r⁶)

• (1/r)

• (1/r⁵)

Which of the following changes in the respective bond order values are caused by removal of an electron from N₂ and F₂ molecules?

• Decrease by 0.5 in both

• Increase by 0.5 in both

• Increase by 0.5 in the former and decrease by 0.5 in the latter

• Decrease by 0.5 in the former and increase by 0.5 in the latter

The hybridised state of bromine in bromine pentafluoride is

• sp³d

• dsp³

• d²sp³

• sp³d²

The correct ascending order of ligand field strength of the given ligands is

• F^- < I^- < CN^- < H₂O < CO

• I^- < F^- < H₂O < CO < CN^-

• I^- < F^- < H₂O < CN^- < CO

• F^- < H₂O < I^- < CN^- < CO

Arrange the following species in the correct order of their stability

C₂, Li₂, O${}_2^{+}$, He${}_2^{+}$

• Li₂ < He${}_2^{+}$ < O${}_2^{+}$ < C₂

• C₂ < O${}_2^{+}$ < Li₂ < He${}_2^{+}$

• He${}_2^{+}$ < Li₂ < C₂ < O${}_2^{+}$

• O${}_2^{+}$ < C₂ < Li₂ < He${}_2^{+}$

Molecular formulae and shapes of some molecules are given below. Choose the incorrect match.

• NH₃ - Trigonal pyramidal

• SF₄ - Tetrahedral

• ClF₃ - T-shaped

• PCl₅ - Triginal bipyramidal

378.

In which one of the following the central atom is sp³ hydridised?

• NH${}_4^{+}$

• BF₃

• SF₆

• PCl₅

The calculated magnetic moment of a divalent ion of an atom with atomic number 24 in aqueus solution is

• 4.90 BM

• 5.92 BM

• 3.87 BM

• 2.84 BM

Molecular shapes of SF₄ ,CF₄ and XeF₄ and the number of lone pairs on the central atom are respectively

• the same, with 1, 2 and 1

• the same with 1, 0 and 1

• different with 0, 1 and 2

• different with 1, 0 and 2