Chapter 11, Problem 11.42E

The following names are incorrect, according to IUPAC rules. Draw the structural formulas and tell why each name is incorrect. Write the correct name for each compound.

a. $\text{1, 2-dimethylpropane}$

b. $\text{3, 4-dimethylpentane}$

c. $\text{2-ethyl-4-methylpentane}$

d. $\text{2-bromo-3-ethylbutane}$

Interpretation Introduction

(a)

Interpretation:

The structural formulas for given compound is to be drawn. The reason as to why the given compound name is incorrect is to be stated. The correct name for the given compound is to be stated.

Concept introduction:

The condensed structural formula of the compound represents the arrangement of atoms by showing specific covalent bonds. The molecular formula represents the atoms and their subscript represents the number of atoms without showing any covalent bonds. The structural formula represents the arrangement of atoms in space.

Answer to Problem 11.42E

The structural formulas for given compound is,

The longest chain in the given compound has four carbon atoms and one methyl group is attached to the second carbon. The correct IUPAC name of the given compound is $\text{2-methylbutane}$.

Explanation of Solution

The given compound is $\text{1, 2-dimethylpropane}$. The longest chain in the given compound has four carbon atoms. The lowest possible number is given to the carbon from which a group is attached. Thus, the parent chain is butane and one methyl group is attached on the second carbon. Thus, the correct IUPAC name of the given compound is $\text{2-methylbutane}$ as shown below.

Figure 1

Conclusion

The structural formulas for given compound is shown in Figure 1. The longest chain in the given compound has four carbon atoms and one methyl group is attached to the second carbon. The correct IUPAC name of the given compound is $\text{2-methylbutane}$.

Interpretation Introduction

(b)

Interpretation:

The structural formulas for given compound is to be drawn. The reason as to why the given compound name is incorrect is to be stated. The correct name for the given compound is to be stated.

Concept introduction:

The condensed structural formula of the compound represents the arrangement of atoms by showing specific covalent bonds. The molecular formula represents the atoms and their subscript represents the number of atoms without showing any covalent bonds. The structural formula represents the arrangement of atoms in space.

Answer to Problem 11.42E

The structural formulas for given compound is,

The lowest possible number is given to the carbon at which a group is attached. Thus, the correct IUPAC name of the given compound is $\text{2, 3-dimethylpentane}$.

Explanation of Solution

The given compound is $\text{3, 4-dimethylpentane}$. The given compound contains five carbon atoms. One methyl group each is attached to the third and fourth carbon atom respectively.

The lowest possible number is given to the carbon from which a group is attached. Thus, the correct IUPAC name of the given compound is $\text{2, 3-dimethylpentane}$ as shown below.

Figure 2

Conclusion

The structural formulas for given compound is shown in Figure 2. The lowest possible number is given to the carbon from which a group is attached. Thus, the correct IUPAC name of the given compound is $\text{2, 3-dimethylpentane}$.

Interpretation Introduction

(c)

Interpretation:

The structural formulas for given compound is to be drawn. The reason as to why the given compound name is incorrect is to be stated. The correct name for the given compound is to be stated.

Concept introduction:

The condensed structural formula of the compound represents the arrangement of atoms by showing specific covalent bonds. The molecular formula represents the atoms and their subscript represents the number of atoms without showing any covalent bonds. The structural formula represents the arrangement of atoms in space.

Answer to Problem 11.42E

The structural formulas for given compound is,

The parent chain is hexane and one methyl group each is attached to second and fourth carbon atom. Thus, the correct IUPAC name of the given compound is $\text{2, 4-dimethylhexane}$.

Explanation of Solution

The given compound is $\text{2-ethyl-4-methylpentane}$. The given compound contains five carbon atoms. One ethyl and one methyl groups are attached to the second and fourth carbon respectively.

The longest chain in the given compound has six carbon atoms. Thus, the parent chain is hexane. The lowest possible number is given to the carbon from which a group is attached. Thus, methyl group are attached to second and fourth carbon. Thus, the correct IUPAC name of the given compound is $\text{2, 4-dimethylhexane}$ as shown below.

Figure 3

Conclusion

The structural formulas for given compound is shown in Figure 3. The parent chain is hexane and one methyl group each is attached to second and fourth carbon atoms. Thus, the correct IUPAC name of the given compound is $\text{2, 4-dimethylhexane}$.

Interpretation Introduction

(d)

Interpretation:

The structural formulas for given compound is to be drawn. The reason as to why the given compound name is incorrect is to be stated. The correct name for the given compound is to be stated.

Concept introduction:

The condensed structural formula of the compound represents the arrangement of atoms by showing specific covalent bonds. The molecular formula represents the atoms and their subscript represents the number of atoms without showing any covalent bonds. The structural formula represents the arrangement of atoms in space.

Answer to Problem 11.42E

The structural formulas for given compound is,

The parent chain is pentane and bromine and methyl group are attached to second and third carbon respectively. Thus, the correct IUPAC name of the given compound is $\text{2-bromo-3-methylpentane}$.

Explanation of Solution

The given compound is $\text{2-bromo-3-ethylbutane}$. The given compound contains four carbon atoms. One ethyl and one bromine atom are attached to the third and second carbon respectively.

The longest chain in the given compound has five carbon atoms. Thus, the parent chain is pentane. The lowest possible number is given to the carbon from which a group is attached. Thus, bromine and methyl group are attached to second and third carbon respectively. Thus, the correct IUPAC name of the given compound is $\text{2-bromo-3-methylpentane}$ as shown below.

Figure 4

Conclusion

The structural formulas for given compound is shown in Figure 4. The parent chain ispentane and bromine and methyl group are attached to second and third carbon respectively. Thus, the correct IUPAC name of the given compound is $\text{2-bromo-3-methylpentane}$.