Problem 27 - 43 Years JEE ADVANCED (1978-2020) + JEE MAIN Chapterwise & Topicwise Solved Papers Chemistry

Question

Monocarboxylic acids are functional isomers of: (a) Ethers (b) Amines (c) Esters (d) Alcohols

Step-by-Step Solution

Answer

(c) Esters

Step 1: Understand Functional Isomers

Functional isomers are compounds with the same molecular formula but different functional groups. This change in the functional group results in different chemical properties.

Step 2: Define Monocarboxylic Acids

Monocarboxylic acids are organic compounds containing one carboxyl group (-COOH). An example is acetic acid, CH₃COOH.

Step 3: List Possible Isomeric Functional Groups

The potential functional groups that can form isomers with monocarboxylic acids, considering the same molecular formula, may include ethers, amines, esters, and alcohols.

Step 4: Choose Chemical Group for Isomerism with Carboxylic Acid

The functional group that often serves as a functional isomer to a carboxylic acid is the ester group. Carboxylic acids can be rearranged to form an ester.

Step 5: Analyze Example of Isomerism

Consider acetic acid (CH₃COOH), a monocarboxylic acid. An isomer is ethyl formate (HCOOCH₃), which is an ester, demonstrating their isomerism.

Step 6: Confirm Correct Answer

Based on the functional isomerism, monocarboxylic acids are functional isomers of esters.

Key Concepts

Monocarboxylic Acids

Monocarboxylic acids are a class of organic compounds that hold one carboxyl group, expressed as \(-COOH\). These acids are a fundamental part of organic chemistry due to their broad range of applications, ranging from culinary uses to industrial applications.
Because of their carboxyl group, they engage in specific reactions typical to acids, such as donating protons to bases. They also participate in reactions that form esters and amides.

• The simplest form of a monocarboxylic acid is formic acid (HCOOH), found in ant venom.
• More commonly known is acetic acid (CH₃COOH), the main component of vinegar.

Understanding monocarboxylic acids involves recognizing how their characteristic carboxyl group influences their chemical behavior and reactivity. This knowledge is crucial when studying their conversion to other functional groups through isomerism.

Ester Functional Group

Esters are organic compounds typically derived from an acid and an alcohol, with water being removed in the process. They contain an ester functional group, symbolized as \(-COOR\), where \(R\) represents a carbon-containing fragment. Esters are noted for their sweet and fruity odors.
One essential feature of esters is their formation through a reaction called esterification, which combines acids and alcohols. In this transformation, the carboxyl group \(-COOH\) from an acid reacts with the hydroxyl group \(-OH\) of an alcohol. The resultant ester demonstrates different properties from its parent acid and alcohol due to the changed functional group.

• Esters like ethyl acetate, \((CH_3COOCH_2CH_3)\), are often used as solvents.
• Many naturally occurring fats and oils are esters of glycerol and fatty acids.

The role of esters in functional isomerism lies in their ability to share formulas with acids, such as monocarboxylic acids, yet differ in structure and properties. This is an illustration of functional isomerism in action.

Organic Chemistry Concepts

Organic chemistry is a vast field focused on the study of carbon-containing compounds. A critical part of this field involves understanding different functional groups, which determine how organic molecules behave and react. Functional isomerism is one of the core concepts within organic chemistry.
Functional isomers are isomers with the same formulas but different functional groups, leading to different chemical properties. This type of isomerism helps explain how diverse molecules can arise from similar starting points, such as how esters are functional isomers of monocarboxylic acids.

• This structural diversity is why organic chemistry is regarded as complex and fascinating.
• Functional groups like hydroxyl (\(-OH\)), carboxyl (\(-COOH\)), and ester (\(-COOR\)) play a large role in this diversity.

By grasping these concepts, students can predict and understand the behavior of various organic molecules, including those with significant industrial and biochemical importance.