Chapter 10, Problem 10.1P

Interpretation Introduction

Interpretation: The structure of six alkenes having molecular formula ${\text{C}}_5{\text{H}}_{\text{10}}$ and a pair of diastereomers are to be shown.

Concept introduction: Alkenes are the compounds in which $\text{C}=\text{C}$ double bond is present. Alkenes can be of two types: terminal alkenes and non-terminal alkenes. When double bond is present at the end of carbon chain, then it is classified as terminal alkene, whereas when double bond is present within carbon chain, then it is classified as non-terminal alkene.

Answer to Problem 10.1P

The structure of six alkenes having molecular formula ${\text{C}}_5{\text{H}}_{\text{10}}$ and a pair of diastereomers are rightfully stated.

Explanation of Solution

The given molecular formula of the compound is ${\text{C}}_5{\text{H}}_{\text{10}}$.

The first possible structure of alkene with molecular formula ${\text{C}}_5{\text{H}}_{\text{10}}$ is shown below.

Figure 1

The first possible structure of alkene contains five carbon and ten hydrogen atoms. The double bond is present between first and second carbon atom.

The second possible structure of alkene with molecular formula ${\text{C}}_5{\text{H}}_{\text{10}}$ is shown below.

Figure 2

The second possible structure of alkene contains five carbon and ten hydrogen atoms. The double bond is present between first and second carbon atom. One methyl substituent is attached to the second carbon atom.

The third possible structure of alkene with molecular formula ${\text{C}}_5{\text{H}}_{\text{10}}$ is shown below.

Figure 3

The third possible structure of alkene contains five carbon and ten hydrogen atoms. The double bond is present between first and second carbon atom. One methyl substituent is attached to the third carbon atom.

The fourth possible structure of alkene with molecular formula ${\text{C}}_5{\text{H}}_{\text{10}}$ is shown below.

Figure 4

The fourth possible structure of alkene contains five carbon and ten hydrogen atoms. The double bond is present between second and third carbon atom. One methyl substituent is attached to the second carbon atom.

The fifth possible structure of alkene with molecular formula ${\text{C}}_5{\text{H}}_{\text{10}}$ is shown below.

Figure 5

The fifth possible structure of alkene contains five carbon and ten hydrogen atoms. The double bond is present between second and third carbon atom. Substituents attached to the second and third carbon atom are on different side.

The sixth possible structure of alkene with molecular formula ${\text{C}}_5{\text{H}}_{\text{10}}$ is shown below.

Figure 6

The sixth possible structure of alkene contains five carbon and ten hydrogen atoms. The double bond is present between second and third carbon atom. Substituents attached to the second and third carbon atom are on same side.

A pair of diastereomers exists when two substituents attached to each of the double bonded carbon atoms are different. The fifth and sixth structure indicates that the substituents bonded to the $\text{C}=\text{C}$ double bond are different from each other.

Therefore, a pair of disatereomers is shown below.

Figure 7

Conclusion

The structure of six alkenes having molecular formula ${\text{C}}_5{\text{H}}_{\text{10}}$ and a pair of diastereomers are rightfully stated.