Problem 115 - A Complete Resource Book in Chemistry for JEE Main

Question

Which is incorrectly matched? Common name \(\quad\) IUPAC name (a) Vanillin 4-hydroxy-3-methoxybenzaldehyde (b) Protocatechual- \(\quad 2,3\)-dihydroxydehyde benzaldehyde (c) Adipic acid hexanl, 6 -dioic acid (d) Pyruvic acid cis-2-methylbut-2-enoic acid

Step-by-Step Solution

Answer

(b) Protocatechual- ,3-dihydroxydehyde benzaldehyde is mismatched.

Step 1: Understand the problem

Identify the common names and their corresponding IUPAC names. We need to check if each pair is correctly matched.

Step 2: Verify Vanillin

Vanillin has the structure of 4-hydroxy-3-methoxybenzaldehyde. This is correctly matched.

Step 3: Verify Protocatechual

Protocatechualdehyde is 3,4-dihydroxybenzaldehyde, not 2,3-dihydroxybenzaldehyde. This indicates a mismatch.

Step 4: Verify Adipic acid

Adipic acid has the IUPAC name hexanedioic acid. The given name `hexanl, 6 -dioic acid` seems incorrect, but it is close enough to potentially be a matching error; we need more context to definitively rule it as correct or incorrect.

Step 5: Verify Pyruvic acid

Pyruvic acid is 2-oxopropanoic acid. The given IUPAC name `cis-2-methylbut-2-enoic acid` is not the correct name for Pyruvic acid, indicating a mismatch.

Key Concepts

Organic Chemistry

Organic chemistry is a branch of chemistry that focuses on the study, formulation, and behavior of organic compounds and materials. These compounds primarily contain carbon atoms bonded with other elements like hydrogen, oxygen, nitrogen, and sulfur. What makes organic chemistry unique is its extensive versatility and complexity:

• Carbon's ability to form stable bonds with many elements.
• The diversity of chemical structures involving chains, rings, and complex configurations.
• Being foundational to understanding broader biological and synthetic chemical processes.

In the provided problem, each chemical name is an organic compound, illustrating the distinctive structures and properties that organic chemists study. Understanding these structural nuances is key to solving problems involving chemical naming.

Functional Groups

Functional groups are specific atoms or clusters of atoms within molecules that have characteristic properties. They play a crucial role in determining the chemical behavior of the compounds. Functional groups can be thought of as the active parts of a molecule that engage in chemical reactions.

• Hydroxyl Group (-OH): Present in both vanillin (4-hydroxy-3-methoxybenzaldehyde) and protocatechualdehyde, contributing to their reactivity and properties.
• Carboxyl Group (-COOH): Seen in adipic acid and pyruvic acid, this group is vital for the compound's acidic nature and reactions.
• Each functional group imparts specific characteristics to a molecule, making them fundamental components in organic chemistry.

Recognizing the functional groups allows chemists to predict the compound's properties and potential reactions, integral in the IUPAC nomenclature process.

Chemical Naming Conventions

Chemical naming conventions, particularly the IUPAC nomenclature, are systematic approaches used to name chemical compounds. This system ensures that each compound has a unique name, facilitating clear communication and understanding across the globe. The process of naming involves several rules:

• Identify the longest carbon chain to determine the base name.
• Number the chain to give the lowest numbers to functional groups and substituents.
• Use prefixes, infixes, and suffixes to indicate the nature and position of functional groups, such as "hydroxy" for an -OH group or "oxo" for a carbonyl group.

In the exercise, properly matching the common name with the IUPAC name involves understanding these conventions. For instance, the term "dihydroxy" in protocatechualdehyde or the "methoxy" group in vanillin's IUPAC name reflect the systematic root of naming. Correct IUPAC names not only denote a precise structure but also aid in deducing the chemical's physical and chemical properties.