Chapter 14, Problem 19A

Interpretation Introduction

Interpretation:

The intramolecular and intermolecular forces in between water molecules are to be predicted.

Concept introduction:

The molecules that are held together by bonds that occur inside the molecule called as intramolecular forces. This force arises by sharing of electrons between covalent bonding. Intermolecular forces exist between molecules. This force arises when molecules with dipole moments are put together. Particularly strong dipole-dipole forces occur between molecule in which hydrogen is bound to highly electronegative atom, such as oxygen, nitrogen, fluorine etc.

Answer to Problem 19A

The forces that connect two hydrogen atoms to an oxygen atom in a water molecule are intramolecular, but the forces that hold water molecules close together in an ice cube are intermolecular.

Explanation of Solution

Water is a polar molecule, it has a dipole moment. Two hydrogen atoms are connected to an oxygen atom by sharing of electrons through covalent bonds. These covalent bonds are held together by intramolecular forces of attraction.

Two water molecules are close together by hydrogen bonding in an ice having strong dipole moments between electronegative oxygen atom (negative end) and two hydrogen atoms (positive end). These hydrogen boning held the water molecules together called as intermolecular forces.

Conclusion

Intramolecular forces are present in an atom while intermolecular forces are present between two or more molecules.