Chapter U2.6, Problem 5E

Interpretation Introduction

(a)

Interpretation:

Molecular formula of hexanol must be given.

Concept introduction:

Molecular formula is the general formula of the molecule which shows the number of different atoms.

Answer to Problem 5E

Molecular formula of hexanol is C₆H₁₄O.

Explanation of Solution

Aliphatic alcohol has general formula C_nH_{2n + 2}O. As in hexanol there are 6 carbon atoms, so total number of hydrogen must be 14. There is one O atom which is present in the hydroxyl (alcoholic OH) functional group.

Interpretation Introduction

(b)

Interpretation:

A possible structural formula of hexanol must be drawn.

Concept introduction:

Structural formula is the representation of a molecule in which the arrangements of all the atoms are shown.

Answer to Problem 5E

Structural formula of hexanol is shown below.

Explanation of Solution

One possible structural formula of hexanol acid is drawn in which all the carbon atoms have 4 bonds. The O has two bonds and two lone pairs of electrons. There is no lone pair on C and H atoms. Hydrogen atoms of the carbon chain are not shown to avoid complexity of the structure.

Many hexanol possibly depend on the position of functional (alcoholic OH) group.

Interpretation Introduction

(c)

Interpretation:

Whether molecular formula or structural formula is more important in determining the smell of the compound must be explained.

Concept introduction:

Structural formula gives more information regarding three dimensional arrangements of atoms and shape of a molecule whereas molecular formula only gives number of different atoms.

Answer to Problem 5E

Structural formula is more important in determining the smell of a compound.

Explanation of Solution

The functional group (OH) present in hexanol is shown in red. The functional group is present in carbon-1. The structure of the hexanol will change if the OH group is present in other carbons. Thus, to get the actual shape of the molecule, structural formula is essential. Many structures can be drawn for a single molecular formula. So, to determine the smell of a compound, the idea of shape of the molecule is important. Thus, structural formula is more important than molecular formula in determining the smell of a molecule.