Chapter 4, Problem 21P

Interpretation Introduction

Interpretation: Different structures for formula C₅H₁₀with one ring should be determined.

Concept introduction: C₅H₁₀have two hydrogen atoms less than the molecular formula of C₅H₁₂, i.e. it contains either a double bond or a cyclic group. So in functional groups, alkenes and cycloalkanes are considered.

Answer to Problem 21P

1. Cyclopentane
2. Methylcyclobutane
3. 1,1-dimethyl cyclopropane
4. 1,2- dimethyl cyclopropane
5. Ethylcyclopropane

Explanation of Solution

Considering the structural formula C₅H₁₀ with a ring, the maximum number of carbon in that ring can be equal to or less than 5.

So the structures will be:

  

Cyclopentane

Other structures are:

Cyclobutane with one methyl substituent which is named as Methylcyclobutane

(According to IUPAC)

  

Cyclopropane with 2 methyl functional group (1, 1-dimethyl cyclopropane )

  

Cyclopropane with 2 methyl functional group, where functional group is attached to the adjacent C atoms of the cyclic groups (1,2- dimethylcyclopropane)

  

cis-1,2-dimethyl cyclopropane trans-1,2-dimethyl cyclopropane

Cyclopropane is another structure with 1 ethyl (CH₂CH₃) functional group is named as Ethylcyclopropane

  

Conclusion

The five different structures can be written for the structural equation C₅H₁₀ and they are Cyclopentane, Methylcyclobutane, 1,1-dimethylcyclopropane, 1,2-dimethyl cyclopropane, ethylcyclopropane.