Ncert Solutions Chemistry Class 11th

4.18. When two dissimilar atoms having different electronegativities combine to form a covalent bond, the bond pair of electrons is not shared equally. The bond pair shifts towards the nucleus of the atom having greater electronegativity. As a result, electron distribution gets distorted and the ele

4.17. Electronegativity: Electronegativity is the tendency of an atom to attract shared pair of electrons towards itself. Electronegativity of any given element is never the same.

It depends on the element it is bonded with in a compound. Electronegativity is a relative quantity and cannot

4.16. Significance of dipole moment are:

In predicting the nature of the molecules: Molecules with specific dipole moments are polar in nature and those of zero dipole moments are non-polar in nature.

In the determination of shapes of molecules.

In calculating the percentage ionic character.

4.15. In CO₂, there are two C=O bonds. Each C=O bond is a polar bond. The net dipole moment of CO₂ molecule is zero. This is possible only if CO₂ is a linear molecule. (O=C=O). The bond dipoles of two C=O bonds cancel the moment of each other.

Whereas, H₂O has a net dipole moment of 1.

4.12. No, these cannot be taken as canonical forms because the positions of atoms have been changed. 

4.11. 

Resonance in CO₃^2-, I, II and III represent the three canonical forms.

In these structures, the position of nuclei is the same.

The Lewis dot structure has two single bonds and one double bond.

All three forms have almost equal energy.

The three forms have same number of paired and unpaired e

4.10. Bond-length: It is the equilibrium distance between the nuclei of two bonded atoms in a molecule. Bond-lengths are measured by spectroscopic methods.

4.9. Bond strength is directly proportional to the bond order. Greater the bond order more is the bond strength.