Problem 30 - 43 Years JEE ADVANCED (1978-2020) + JEE MAIN Chapterwise & Topicwise Solved Papers Chemistry

Question

The carboxyl functional group (- COOH) is present in (a) picric acid (b) barbituric acid (c) ascorbic acid (d) aspirin

Step-by-Step Solution

Answer

The carboxyl group is present in barbituric acid and aspirin.

Step 1: Define the Carboxyl Group

The carboxyl functional group is represented as \(-COOH\). It is a common functional group in organic acids and is characterized by a carbonyl (C=O) and a hydroxyl (O-H) group connected to the same carbon atom.

Step 2: Analyze Picric Acid

Picric acid is structurally represented by 2,4,6-trinitrophenol. Here, the functional group is a phenol \(-OH\), along with nitro groups, but not a carboxyl group \(-COOH\).

Step 3: Analyze Barbituric Acid

Barbituric acid is the parent compound of barbiturate drugs and contains the \(-COOH\) group in its structure, along with nitrogen and keto groups.

Step 4: Analyze Ascorbic Acid

Ascorbic acid, commonly known as Vitamin C, does not contain a \(-COOH\) group. It contains enediol, lactone, and ether functionalities.

Step 5: Analyze Aspirin

Aspirin, or acetylsalicylic acid, contains the \(-COOH\) group as part of its structure. It also contains an ester group.

Step 6: Conclusion

Based on the analysis of each compound, both Aspirin and Barbituric acid contain the carboxyl \(-COOH\) group.

Key Concepts

Organic Acids

Organic acids are a class of compounds that typically contain a carboxyl functional group \((-COOH)\), which is responsible for their acidic properties. These acids are prevalent in nature and are significant in various biochemical processes. Understanding the nature and behavior of organic acids is essential for comprehending many chemical reactions and processes.
Generally, when dissolved in water, these acids donate a proton \(H^+\) due to the carboxyl group, resulting in the formation of their conjugate base. This proton donation is what defines them as acids. Organic acids like acetic acid, found in vinegar, and citric acid, found in citrus fruits, are common examples where you can observe these properties.
It’s important to note that not all acids that have a hydrogen atom are classified as organic acids – this classification usually pertains to those with specific functional groups like the carboxyl group.

Chemical Structure Analysis

Chemical structure analysis involves examining the arrangement of atoms within a molecule to understand its properties and reactivity. Such analysis is crucial for identifying whether a given compound possesses certain functional groups. In the context of our problem, determining the presence of the carboxyl \((-COOH)\) group in various compounds makes use of this technique.
For instance, barbituric acid and aspirin both contain the \((-COOH)\) group. By analyzing their structures, we notice that:

• Barbituric Acid: Contains nitrogen atoms and a keto group, along with the carboxyl group. It forms the basis for several barbiturate drugs.
  
• Aspirin: Also known as acetylsalicylic acid, features an ester group in addition to the carboxyl group.
  

Understanding the structural composition of molecules helps in identifying their potential applications and interactions in chemical synthesis or biological processes.

Functional Groups in Chemistry

Functional groups are specific groupings of atoms within molecules that are responsible for the characteristic reactions of those molecules. In organic chemistry, they are crucial as they determine many of the chemical properties of molecules.
The carboxyl group \((-COOH)\) exemplifies one such functional group common in organic chemistry. Its presence is responsible for the acidic nature of organic acids. When analyzing chemical compounds, identifying functional groups can give insight into how a compound might react chemically.
Common types of functional groups include:

• Hydroxyl \((-OH)\): Found in alcohols and phenols.
• Carbonyl \(C=O\): Present in aldehydes and ketones.
• Amino \((-NH_2)\): Found in amines and amino acids.
• Carboxyl \((-COOH)\): Present in most organic acids, responsible for their acidity.

Functional groups not only dictate the reactivity of molecules but also their physical properties like solubility and boiling point. By identifying and understanding these groups, chemists can predict and manipulate the behavior of molecules in chemical reactions.