Chapter 15, Problem 15.20P

(a)

Interpretation Introduction

Interpretation:

The name of the given compound has to be given.

Concept Introduction:

The hydrocarbons which contain only single bonds are said to be Alkanes.  The general formula for alkanes can be given as ${\text{C}}_{\text{n}}{\text{H}}_{\text{2n+2}}$.  All carbon atoms are ${\text{sp}}^{\text{3}}$ hybridized.

The Alkanes are named following some rules:

• The name of the alkane is given by the number of carbon atoms present in the chain.  It is said to be Root of the alkane.

Root = number of carbon atoms in chain.

• To name the root, for one carbon atom, the root name use is meth-.  For two carbon atoms, the root name is eth-, for three carbon atoms, it is prop-, for four carbon atoms, it is but-, for five carbon atoms, it is pent- and so on.
• The root name is followed by Suffix.  Suffix indicates the functional group present in the compound.  It is placed after the root name.

Suffix = name of the functional group present in the compound.

• The root name also contains Prefix.  Prefix is the groups attached to the root.  It indicates the branched carbon atoms on the root chain and name according to the root specifying the carbon number on which it is placed.  It contains –yl in name end.  The prefix is placed before the root name.

Prefix = name of the branched carbon atoms on chain.

• The name of the alkane is given in the form

Prefix + Root + Suffix

(b)

Interpretation Introduction

Interpretation:

The name of the given compound has to be given.

Concept Introduction:

The hydrocarbons which contain only single bonds are said to be cycloalkanes.  The general formula for alkanes can be given as ${\text{C}}_{\text{n}}{\text{H}}_{\text{2n}}$.  All carbon atoms are ${\text{sp}}^{\text{3}}$ hybridized.

The cycloalkanes are named following some rules:

• The name of the alkane is given by the number of carbon atoms present in the ring.  It is said to be Root of the alkane.

Root = number of carbon atoms in ring.

• To name the root, for one carbon atom, the root name use is meth-.  For two carbon atoms, the root name is eth-, for three carbon atoms, it is prop-, for four carbon atoms, it is but-, for five carbon atoms, it is pent- and so on.
• The root name is followed by Suffix.  Suffix indicates the functional group present in the compound.  It is placed after the root name.

Suffix = name of the functional group present in the compound.

• The root name also contains Prefix.  Prefix is the groups attached to the root.  It indicates the branched carbon atoms on the root chain and name according to the root specifying the carbon number on which it is placed.  It contains –yl in name end.  The prefix is placed before the root name.

Prefix = name of the branched carbon atoms on chain.

• The name of the alkane is given in the form

Prefix + Root + Suffix

(c)

Interpretation Introduction

Interpretation:

The structure of the given compound (1,2-diethylcyclopentane) has to be drawn.

Concept Introduction:

The structure of the compound is given by its systematic name.

To give the structure from the name of the compound, the root name has to be identified.  The root name indicates the number of carbon atoms present in the longest chain.

Then the functional group (suffix) has to be identified.  It indicates whether any functional groups are present in the compound, it also gives whether the compound is an alkane or alkene or alkyne.

The prefix of the name indicates the branched groups and their positions on the carbon chain.

The name of the compound is in the form

Prefix + Root + Suffix

(b)

Interpretation Introduction

Interpretation:

The structure of the given compound (2,4,5-trimethylnonane) has to be drawn.

Concept Introduction:

The structure of the compound is given by its systematic name.

To give the structure from the name of the compound, the root name has to be identified.  The root name indicates the number of carbon atoms present in the longest chain.

Then the functional group (suffix) has to be identified.  It indicates whether any functional groups are present in the compound, it also gives whether the compound is an alkane or alkene or alkyne.

The prefix of the name indicates the branched groups and their positions on the carbon chain.

The name of the compound is in the form

Prefix + Root + Suffix