Chapter 12, Problem 14A

Interpretation Introduction

Interpretation:

The importance of polarity in water is to be discussed.

Concept introduction:

A covalent bond which is formed by two different atom is polar in nature and its polarity is numerically calculated using dipole moment.

Dipole moment of a bond is defined as product of the charge carried by atom multiplied by distance between the charges.

Let’s consider a bond $A-B$ having charge $\partial +and\partial -$ with $r$ distance apart, dipole moment is given by:

  $dipolemoment=q\times r$

The units of dipole moment are $esu-cmandDebye(D)$

Answer to Problem 14A

The presence of dipole moment in water makes it polar and allows it to form hydrogen bonding, to dissolve many compounds in it.

Explanation of Solution

Water is polar because electronegativity of oxygen is more than hydrogen. Oxygen pulls electron density towards itself making hydrogen partially positive. Thus, water is polar. And as the solvency rule says- like dissolves like. So, polar nature of water helps it to work as solvent for many solutes.

  

Conclusion

Thus, polarity in water helps it be a good solvent.