Page 2 - HA

(18)Explain why BeH2 molecule has a zero dipole moment although the

Be-H bonds are polar.

(19)Arrange the bonds in order of increasing ionic character in the

molecules: LiF, K2O, N2, SO2 and ClF3.

(20)Although both CO2 and H2O are triatomic molecules, the shape of

H2O molecule is bent while that of CO2 is linear. Explain this on the
basis of dipole moment.
(21)How do you express the bond strength in terms of bond order ?

(22)What is the shape of CO molecule ?
2

(23)Why bond angle of NH is more than PH ?
3
3
(24)He molecule does not exist, explain according to VBT.
2

(25)Why sigma bond is stronger than pi bond ?

(26)Distinguish between a sigma and a pi bond.

(27)What is the total number of sigma and pi bonds in the following

molecules ? (a) C2H2 (b) C2H4

(28)What do you understand by bond pairs and lone pairs of electrons ?
Illustrate by giving one exmaple of each type.

(29)Explain the formation of H2 molecule on the basis of valence bond
theory.

(30)What is the shape of SF molecule ?
6
(31)How many bond pairs and lone pairs are present in the molecule
SF ?
4
(32)Define resonance.

(33)Write the resonance structure for SO3. and .
(36)What is meant by hybridisation of atomic orbitals?
(34) Write the resonance structure for NO2.
−
(35) Write the resonance structure for NO3 .