Chapter 3, Problem 3.3P

Draw the structure of a compound fitting each description:

a. an aldehyde with molecular formula ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}\text{O}$.

b. a ketone with molecular formula ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}\text{O}$.

c. a carboxylic acid with molecular formula ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}{\text{O}}_2$.

d. an ester with molecular formula ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}{\text{O}}_2$.

Interpretation Introduction

(a)

Interpretation: The structure of an aldehyde with molecular formula ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}\text{O}$ is to be drawn.

Concept introduction: Functional groups are specific substituents present in the molecule that is responsible for the characteristic chemical reactions. For example, functional groups possess a carbonyl group includes aldehydes, ketones, carboxylic acids, amides, esters and acid chlorides. An organic compound containing $-\text{CHO}$ functional group is known as aldehyde.

Answer to Problem 3.3P

The structure of an aldehyde with molecular formula ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}\text{O}$ is,

Explanation of Solution

The given molecular formula is ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}\text{O}$. The double bond equivalent in the organic molecule is calculated by the formula,

$\text{DBE}=\text{C}-\frac{\text{H}}{\text{2}}+1$

Where,

• C is the number of carbon atoms.

• H is the number of hydrogen atoms.

Substitute the values of number of carbon atoms and hydrogen atoms in the above formula to calculate the number of double bond in compound ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}\text{O}$.

$\begin{array}{rll}\text{DBE}& =& 4-\frac{8}{\text{2}}+1\\ & =& 4-4+1\\ & =& +1\end{array}$

Therefore, the given compound has one double bond with an aldehydic functional group. Hence, the structure an aldehyde with molecular formula ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}\text{O}$ is shown below.

Figure 1

Conclusion

The structure of an aldehyde with molecular formula ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}\text{O}$ is shown in Figure 1.

Interpretation Introduction

(b)

Interpretation: The structure of a ketone with molecular formula ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}\text{O}$ is to be drawn.

Concept introduction: Functional groups are specific substituents present in the molecule that is responsible for the characteristic chemical reactions. For example, functional groups possess a carbonyl group includes aldehydes, ketones, carboxylic acids, amides, esters and acid chlorides. An organic compound containing $-\text{CO}-$ functional group is known as ketone.

Answer to Problem 3.3P

The structure of a ketone with molecular formula ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}\text{O}$ is,

Explanation of Solution

The given molecular formula is ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}\text{O}$. The double bond equivalent in the organic molecule is calculated by the formula,

$\text{DBE}=\text{C}-\frac{\text{H}}{\text{2}}+1$

Where,

• C is the number of carbon atoms.

• H is the number of hydrogen atoms.

Substitute the values of number of carbon atoms and hydrogen atoms in the above formula to calculate the number of double bond in compound ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}\text{O}$.

$\begin{array}{rll}\text{DBE}& =& 4-\frac{8}{\text{2}}+1\\ & =& 4-4+1\\ & =& +1\end{array}$

Therefore, the given compound has one double bond with a ketone functional group. Hence, the structure a ketone with molecular formula ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}\text{O}$ is shown below.

Figure 2

Conclusion

The structure of a ketone with molecular formula ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}\text{O}$ is shown in Figure 2.

Interpretation Introduction

(c)

Interpretation: The structure of a carboxylic acid with molecular formula ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}{\text{O}}_2$ is to be drawn.

Concept introduction: Functional groups are specific substituents present in the molecule that is responsible for the characteristic chemical reactions. For example, functional groups possess a carbonyl group includes aldehydes, ketones, carboxylic acids, amides, esters and acid chlorides. An organic compound containing $-\text{COOH}$ functional group is known as carboxylic acid.

Answer to Problem 3.3P

The structure of a carboxylic acid with molecular formula ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}{\text{O}}_2$ is,

Explanation of Solution

The given molecular formula is ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}{\text{O}}_2$. The double bond equivalent in the organic molecule is calculated by the formula,

$\text{DBE}=\text{C}-\frac{\text{H}}{\text{2}}+1$

Where,

• C is the number of carbon atoms.

• H is the number of hydrogen atoms.

Substitute the values of number of carbon atoms and hydrogen atoms in the above formula to calculate the number of double bond in compound ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}{\text{O}}_2$.

$\begin{array}{rll}\text{DBE}& =& 4-\frac{8}{\text{2}}+1\\ & =& 4-4+1\\ & =& +1\end{array}$

Therefore, the given compound has one double bond with a carboxylic acid functional group. Hence, the structure a carboxylic acid with molecular formula ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}{\text{O}}_2$ is shown below.

Figure 3

Conclusion

The structure of a carboxylic acid with molecular formula ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}{\text{O}}_2$ is shown in Figure 3.

Interpretation Introduction

(d)

Interpretation: The structure of an ester with molecular formula ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}{\text{O}}_2$ is to be drawn.

Concept introduction: Functional groups are specific substituents present in the molecule that is responsible for the characteristic chemical reactions. For example, functional groups possess a carbonyl group includes aldehydes, ketones, carboxylic acids, amides, esters and acid chlorides. An organic compound containing $\text{RCOOR}$ functional group is known as ester.

Answer to Problem 3.3P

The structure of an ester with molecular formula ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}{\text{O}}_2$ is,

Explanation of Solution

The given molecular formula is ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}{\text{O}}_2$. The double bond equivalent in the organic molecule is calculated by the formula,

$\text{DBE}=\text{C}-\frac{\text{H}}{\text{2}}+1$

Where,

• C is the number of carbon atoms.

• H is the number of hydrogen atoms.

Substitute the values of number of carbon atoms and hydrogen atoms in the above formula to calculate the number of double bond in compound ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}{\text{O}}_2$.

$\begin{array}{rll}\text{DBE}& =& 4-\frac{8}{\text{2}}+1\\ & =& 4-4+1\\ & =& +1\end{array}$

Therefore, the given compound has one double bond with an ester functional group. Hence, the structure an ester with molecular formula ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}{\text{O}}_2$ is shown below.

Figure 4

Conclusion

The structure of an ester with molecular formula ${\text{C}}_{\text{4}}{\text{H}}_{\text{8}}{\text{O}}_2$ is shown in Figure 4.