Chapter 6, Problem 29A

Summary Introduction

To write:

The relationship between polar molecule and hydrogen bond.

Introduction:

Compounds like water, salt, etc., are formed when two substances are combined together. The force that holds the substances together is called a chemical bond. Chemical bonds are of two types- covalent and ionic bonds. Covalent bond is formed by sharing of electrons. An ionic bond results from electrical attraction between two oppositely charged atoms or group of atoms. Substances formed by ionic bonds are called ionic compounds.

Explanation of Solution

A molecule is a compound in which the atoms are held together by covalent bonds. Water is a molecule formed by covalent bonds that link two hydrogen atoms with an oxygen atom. Molecules that have an unequal distribution of charges are called polar molecules. Polarity is the property of having two opposite poles i.e. they have oppositely charged regions. The molecules of water have unequal distribution of electrons. A weak electrostatic attraction is formed when a charged region of a polar molecule comes in contact with the charged region of another polar molecule. The force of attraction between the electronegative atom and hydrogen molecules is known as hydrogen bond. Water has a bent shape and the electrons are not shared equally between hydrogen and oxygen, therefore hydrogen bonds form among the molecules.

Conclusion

Polar molecules are those that have oppositely charged regions. The force of attraction between hydrogen and an electronegative atom is known as hydrogen bond.