Chapter 15, Problem 15.1E

Interpretation Introduction

Interpretation:

The structural features of the carboxylic acid functional group are to be stated. The difference in the structure of carboxylic acid from the structures of an alcohol, an aldehyde or a ketone is to be stated.

Concept introduction:

A carbonyl group has a carbon atom that is connected to an oxygen atom through a double bond and single bonded to two other carbon atoms respectively.

• Aldehydes and ketones possess carbonyl functional group in their parent chain.

• The alcohols contain hydroxyl $\left(\text{OH}\right)$ functional group in their parent chain.

• The carboxylic acids contain carboxylic $\left(\text{COOH}\right)$ functional group in their parent chain.

Answer to Problem 15.1E

The structure of carboxylic acid functional group is shown below.

The structure of carboxylic acid functional group is different from alcohols, aldehydes or ketones because it possesses both carbonyl group and hydroxyl group. On the other hand, alcohols has only hydroxyl group and aldehydes or ketones contain only carbonyl group in their structures.

Explanation of Solution

The carboxylic acid functional group has a carbon atom bonded to an oxygen atom by a double bond and bonded to a hydroxyl group $\left(\text{OH}\right)$ by a single bond. The structure of carboxylic acid functional group possesses both carbonyl group and hydroxyl group. The structure of carboxylic acid functional group is shown below.

Figure 1

Aldehydes and ketones contain carbonyl functional group in their parent chain. The structural formula of an aldehyde is $\text{R}-\text{CO}-\text{H}$ and the structural formula of a ketone is $\text{R}-\text{CO}-\text{R}$.

The structure of carboxylic acid functional group is different from both aldehydes and ketones because it has hydroxyl group in addition to the carbonyl group.

The alcohols contain only hydroxyl $\left(\text{OH}\right)$ functional group. The structure of carboxylic acid functional group is different from alcohols because it has carbonyl group in addition to the hydroxyl group. The structures of carboxylic acid, aldehyde, ketone and alcohol functional groups are shown below.

Figure 2

Conclusion

The carboxylic acid functional group structure is shown in Figure 1.

The difference in the structure of carboxylic acid from the structures of an alcohol, an aldehyde or a ketone is rightfully stated.