Problem 12 - Arihant Objective Approach to Organic Chemistry for IIT JEE and NEET all Medical Entrances Part 4

Question

Gammexane is: |CBSE \(1999 \mid\) (a) chlorobenzene (b) benzylchloride (c) bromobenzene (d) benzenehexachloride

Step-by-Step Solution

Answer

Gammexane is benzenehexachloride (option d).

Step 1: Understanding the Options

We need to identify which chemical compound is Gammexane from the given options. Let's look at what each option represents in terms of its chemical structure.

Step 2: Option A: Chlorobenzene

Chlorobenzene is a benzene ring with a single chlorine atom attached. Its molecular formula is C₆H₅Cl.

Step 3: Option B: Benzylchloride

Benzyl chloride consists of a benzene ring with a CH₂Cl group attached. Its molecular formula is C₆H₅CH₂Cl.

Step 4: Option C: Bromobenzene

Bromobenzene is a benzene ring with a single bromine atom attached. Its molecular formula is C₆H₅Br.

Step 5: Option D: Benzenehexachloride

Benzenehexachloride (BHC) is composed of a benzene ring with six chlorine atoms added in a specific configuration. Its molecular formula is C₆H₆Cl₆ and it is commonly known as lindane or Gammexane.

Step 6: Conclusion - Identify Gammexane

Having analyzed each option, we can conclude that benzenehexachloride, also known as lindane, matches the common name Gammexane. This compound is option D.

Key Concepts

Chemical Structure Identification

Chemical structure identification is the process of determining the arrangement of atoms within a molecule. This is essential when distinguishing between different chemical compounds, especially when they have similar molecular formulas. In this exercise, we aim to identify Gammexane, which involves discerning the unique arrangement of chlorine and benzene.
Understanding the small structural differences is crucial:

• Chlorobenzene: A benzene ring with one chlorine atom (C₆H₅Cl).
• Benzylchloride: A benzene ring with a CH₂Cl group (C₆H₅CH₂Cl).
• Bromobenzene: A benzene ring with one bromine atom (C₆H₅Br).
• Benzenehexachloride: A benzene ring with six chlorine atoms (C₆H₆Cl₆), known as Gammexane.

By identifying these structural arrangements, you associate different functionalities and applications to each compound. It's like recognizing patterns in a puzzle you are trying to solve. Once you see the pattern, identifying the right chemical structure becomes manageable.

Benzene Derivatives

Benzene derivatives are compounds that include the benzene ring as part of their chemical structure. Benzene is a simple aromatic ring that serves as a building block for many chemical compounds, including Gammexane.
It is the chemical variations around this ring that create distinct compounds.

• In chlorobenzene, a chlorine atom substitutes one hydrogen of benzene.
• In benzylchloride, a CH₂Cl group is added to the benzene ring.
• In bromobenzene, a bromine atom replaces one hydrogen atom.
• Finally, in benzenehexachloride, six chlorine atoms alter the benzene configuration, forming Gammexane.

The peculiar properties of these derivatives depend heavily on their substituents. Therefore, even slight changes in the chemical groups attached to the benzene ring can lead to significantly different chemical properties and uses.

CBSE Chemistry Questions

The CBSE chemistry exams often include questions that test students' ability to identify different chemical compounds from a list, making understanding topics like benzene derivatives essential. The exercise given is a practical example of such a question type.
When preparing for CBSE exams, focus on:

• Comprehending molecular structures: Understanding how atoms are arranged within molecules.
• Recognizing functional groups: Identifying characteristics like hydroxyl, halogens, and amine groups.
• Memorizing key derivatives: Knowing well-known benzene derivatives and their structures.
• Utilizing nomenclature skills: Applying traditional chemical naming conventions to identify or deduce chemical formulas.

These challenges are designed to ensure that students not only memorize chemical formulas but also develop an understanding of how different molecular structures influence the behavior and use of compounds in chemistry.