Chapter 1, Problem 46P

(a)

Interpretation Introduction

Interpretation:Constitutional isomer possible for ${\text{C}}_{\text{5}}{\text{H}}_{\text{12}}$ should be constructed and the condensed and bond line formulas should be drawn.

Concept introduction:There are three ways of representation of molecular structures. The hashed and wedged formulas have three types of bonds. The bond above the plane is represented by bold hash while bonds behind the plane are represented by wedge. The bonds in plane are represented by normal bonds.

Bond-line formula depicts the zig-zag framework of carbon chain with attached substituents. The terminal position represents a methyl while the non-terminal is for methylene group. For instance, the propane is written in this notation as follows:

  

Molecules that possess identical molecular formula but vary in the manner of their connectivity of the bonds are referred to as structural isomers. These are essentially found in alkanes that can be branched by removal of $\text{H}$ group and its replacement with some alkyl group.

For instance, the smallest branched alkane possible is $\text{2-methylpropane}$ . Its molecular formula is identical with butane ${\text{C}}_{\text{4}}{\text{H}}_{\text{10}}$ but it has different connectivity. The molecular models of $\text{n-butane}$ and $\text{2-methylpropane}$ are illustrated below.

  

The two compounds, in fact, constitute a pair of constitutional isomers. These kinds of isomers are formed by cleavage and replacement of bonds, unlike the conformational isomers that result due to rotation around the bond.The structural isomers possible for a given alkane increase rapidly with a number of carbon atoms. This is justified as for alkanes higher than propane more ways exist to connect the carbon atoms.

(b)

Interpretation Introduction

Interpretation: Constitutional isomer possible for ${\text{C}}_3{\text{H}}_8\text{O}$ should be constructed and the condensed and bond line formulas should be drawn.

Concept introduction:There are three ways of representation of molecular structures. The hashed and wedged formulas have three types of bonds. The bond above the plane is represented by bold hash while bonds behind the plane are represented by wedge. The bonds in plane are represented by normal bonds.

Bond-line formula depicts the zig-zag framework of carbon chain with attached substituents. The terminal position represents a methyl while the non-terminal is for methylene group. For instance, the propane is written in this notation as follows:

  

Molecules that possess identical molecular formula but vary in the manner of their connectivity of the bonds are referred to as structural isomers. These are essentially found in alkanes that can be branched by removal of $\text{H}$ group and its replacement with some alkyl group.

For instance, the smallest branched alkane possible is $\text{2-methylpropane}$ . Its molecular formula is identical with butane ${\text{C}}_{\text{4}}{\text{H}}_{\text{10}}$ but it has different connectivity. The molecular models of $\text{n-butane}$ and $\text{2-methylpropane}$ are illustrated below.

  

The two compounds, in fact, constitute a pair of constitutional isomers. These kinds of isomers are formed by cleavage and replacement of bonds, unlike the conformational isomers that result due to rotation around the bond.The structural isomers possible for a given alkane increase rapidly with a number of carbon atoms. This is justified as for alkanes higher than propane more ways exist to connect the carbon atoms.