Question

Which of the following compounds can be classified as aryl halides? (A) $p-{\mathrm{ClC}}_6{\mathrm{H}}_4{\mathrm{CH}}_2\mathrm{CH}{\left({\mathrm{CH}}_3\right)}_2$ (B) $p-{\mathrm{CH}}_3\mathrm{CHCl}\left({\mathrm{C}}_6{\mathrm{H}}_4\right){\mathrm{CH}}_2{\mathrm{CH}}_3$ (C) $o-{\mathrm{BrH}}_2\mathrm{C}-{\mathrm{C}}_6{\mathrm{H}}_4\mathrm{CH}\left({\mathrm{CH}}_3\right){\mathrm{CH}}_2{\mathrm{CH}}_3$ (D) ${\mathrm{C}}_6{\mathrm{H}}_{11}-\mathrm{Cl}$

Short answer

Compounds (A) and (C) can be classified as aryl halides: (A) $p-{\mathrm{ClC}}_6{\mathrm{H}}_4{\mathrm{CH}}_2\mathrm{CH}{\left({\mathrm{CH}}_3\right)}_2$ (C) $o-{\mathrm{BrH}}_2\mathrm{C}-{\mathrm{C}}_6{\mathrm{H}}_4\mathrm{CH}\left({\mathrm{CH}}_3\right){\mathrm{CH}}_2{\mathrm{CH}}_3$

Step-by-step solution

Analyze compound (A)

For compound (A), we have ${\displaystyle p-{\mathrm{ClC}}_6{\mathrm{H}}_4{\mathrm{CH}}_2\mathrm{CH}{\left({\mathrm{CH}}_3\right)}_2}$. We observe that there is a Chlorine (Cl) atom directly bonded to the aromatic ring at the para position. Therefore, compound (A) is an aryl halide.

Analyze compound (B)

For compound (B), we have ${\displaystyle p-{\mathrm{CH}}_3\mathrm{CHCl}\left({\mathrm{C}}_6{\mathrm{H}}_4\right){\mathrm{CH}}_2{\mathrm{CH}}_3}$. Although there is a Chlorine (Cl) atom in this compound, it is not directly bonded to the aromatic ring. Instead, it's bonded to a carbon atom that is para to the ring. Therefore, compound (B) is not an aryl halide.

Analyze compound (C)

For compound (C), we have ${\displaystyle o-{\mathrm{BrH}}_2\mathrm{C}-{\mathrm{C}}_6{\mathrm{H}}_4\mathrm{CH}\left({\mathrm{CH}}_3\right){\mathrm{CH}}_2{\mathrm{CH}}_3}$. In this compound, a Bromine (Br) atom is directly bonded to the aromatic ring at the ortho position. Thus, compound (C) is an aryl halide.

Analyze compound (D)

For compound (D), we have ${\displaystyle {\mathrm{C}}_6{\mathrm{H}}_{11}-\mathrm{Cl}}$. In this compound, the Chlorine (Cl) atom is bonded to a non-aromatic carbon chain and not to an aromatic ring. Therefore, compound (D) is not an aryl halide.

Conclusion

Based on our analysis, compounds (A) and (C) are the aryl halides: (A) $p-{\mathrm{ClC}}_6{\mathrm{H}}_4{\mathrm{CH}}_2\mathrm{CH}{\left({\mathrm{CH}}_3\right)}_2$ (C) $o-{\mathrm{BrH}}_2\mathrm{C}-{\mathrm{C}}_6{\mathrm{H}}_4\mathrm{CH}\left({\mathrm{CH}}_3\right){\mathrm{CH}}_2{\mathrm{CH}}_3$

Key concepts

Organic Chemistry

Organic chemistry is the fascinating branch of chemistry that studies the structure, properties, and reactions of organic compounds. These compounds are primarily made of carbon atoms, often in combination with elements like hydrogen, oxygen, and nitrogen. Carbon's unique ability to form stable bonds with itself and other elements leads to a vast number of possible molecules. This, in turn, forms the basics of organic chemistry, allowing for diverse molecular structures and complex reactions.
Organic chemistry is not only theoretically exciting but also extremely practical. It is instrumental in developing pharmaceuticals, petrochemicals, and even materials like plastics. Its study involves understanding how different compounds interact and transform, paving the way for innovations in various fields.
Learning organic chemistry equips students with critical thinking and analytical skills, vital in many scientific careers. Its concepts are central to understanding advanced topics, such as biochemical pathways and synthetic organic chemistry.

Aromatic Compounds

Aromatic compounds belong to a class of organic molecules characterized by their stability and unique bonding arrangement, known as "aromaticity." These compounds typically contain at least one benzene ring, a six-carbon ring with alternating single and double bonds. The enduring nature of aromatic compounds stems from this electron configuration, forming what is known as a conjugated pi electron system.
Aromaticity contributes to the chemical properties and reactivity of these compounds. Due to their stability, aromatic compounds often undergo substitution reactions rather than addition reactions. This makes them suitable for forming more complex molecules. The word 'aromatic' initially referred to the fragrant nature of these compounds; however, many aromatic compounds do not have distinct smells.
Understanding aromatic compounds is foundational in organic chemistry, particularly when studying aryl halides, which involve halogens directly bonded to benzene rings or other aromatic systems.

Halogenation

Halogenation, in organic chemistry, refers to the process of adding halogens (like fluorine, chlorine, bromine, or iodine) to organic compounds. This can change the chemical and physical properties of the compounds significantly. In the context of aromatic compounds, halogenation typically involves substitution reactions where a hydrogen atom on the aromatic ring is replaced by a halogen.
Aryl halides are aromatic compounds where at least one of the hydrogen atoms in the benzene ring is substituted by a halogen. Such transformations are fundamental in organic synthesis, leading to products used in various industries, including pharmaceuticals and agrochemicals.
Halogenation can be accomplished through direct addition, using halogen elements, or through more complex reactions involving other halogenating agents. Mastering these methods is crucial for students studying organic chemistry, as it builds understanding of reactivity and molecular transformation principles.

JEE Advanced

JEE Advanced is one of the most challenging engineering entrance exams in India. It demands a deep understanding of various subjects, including chemistry. For organic chemistry, key concepts like aryl halides and their properties are frequently tested.
Candidates need to be proficient in identifying different types of organic compounds, predicting their reactivity and properties. For instance, recognizing aryl halides involves understanding their formation through halogenation of aromatic compounds and their significance in synthetic chemistry.
Preparation for JEE Advanced requires students not only to memorize facts but to develop a robust comprehension of the underlying principles of organic chemistry. This involves extensive problem-solving practice and conceptual clarity of how reactions, like halogenation, fit into the larger framework of organic synthesis.