Chapter 13, Problem 2PE

Interpretation Introduction

Interpretation:

The increasing order of ${\text{H}}_{\text{2}}\text{S}$, ${\text{H}}_{\text{2}}\text{Se}$ and ${\text{H}}_{\text{2}}\text{O}$ molecules that are polar have to be arranged.

Concept Introduction:

Molecules that have uneven electrons distributed among the bonded atoms are termed as polar molecules. In polar molecules, bonded atoms have difference in their electronegativity.

Polarity of the molecule depends on the dipole moment. Dipole moment is directly related to bond length and bond length depends upon the electronegativity of the atom. Therefore, atom with more electronegativity attracts electrons towards it that in turn shortens the bond length of the molecule. With decrease in bond length, dipole moment of the molecule decreases. As dipole moment decreases, molecule becomes less polar. Therefore, as electronegativity increases, polarity of the molecule decreases.