Question

Which of the following is a \(3^{\circ}\) amine? (A) 1 -methylcyclohexylamine (B) Triethylamine (C) tert-butylamine (D) N-methyl aniline

Short answer

The correct answer is (B) Triethylamine, as it has a nitrogen atom bonded to three ethyl groups and is a 3° amine.

Step-by-step solution

Identify the structure of the given options

Let's determine the structure of each option: (A) 1 -methylcyclohexylamine: This compound is a cyclohexylamine with a methyl group attached to the first carbon. (B) Triethylamine: This compound has a nitrogen atom bonded to three ethyl groups. (C) tert-butylamine: This compound has a nitrogen atom bonded to a tert-butyl group. (D) N-methyl aniline: This compound is an aniline with a methyl group attached to the nitrogen atom.

Determine which option is a 3° amine

Now, let's analyze which of these options has a nitrogen atom bonded to three carbon-containing groups: (A) 1 -methylcyclohexylamine: There is a nitrogen atom bonded to a cyclohexyl group and a methyl group. It is a 2° amine. (B) Triethylamine: There is a nitrogen atom bonded to three ethyl groups. It is a 3° amine. (C) tert-butylamine: There is a nitrogen atom bonded to only one tert-butyl group. It is a 1° amine. (D) N-methyl aniline: There is a nitrogen atom bonded to a phenyl group and a methyl group. It is a 2° amine.

Identify the correct answer

Based on our analysis, we can see that among the given options: Triethylamine (B) is a 3° amine, as it has a nitrogen atom bonded to three ethyl groups. Hence, the answer is (B) Triethylamine.

Key concepts

Understanding Organic Chemistry

Organic chemistry is a sub-discipline of chemistry that involves the scientific study of the structure, properties, and reactions of organic compounds and materials, that is, substances containing carbon atoms. This field is fundamental for the development of pharmaceuticals, plastics, fuels, and much more.

In the context of identifying amines, organic chemistry provides the tools and language to understand how different groups attached to a nitrogen atom influence its properties. The classification of amines as primary, secondary, or tertiary (1°, 2°, or 3°) is based on the number of carbon-containing groups bound to the nitrogen. Thus, grasping the intricacies of organic chemistry not only helps in solving problems like identifying a 3° amine but also lays down the groundwork for innovation in various industries.

Amine Classification Explained

Amines are classified based on the number of alkyl or aromatic substituents attached to the nitrogen atom. The classification is straightforward yet critical for understanding amines' reactivity and properties:

• Primary (1°) Amines: They have one alkyl or aromatic substituent attached to the nitrogen atom.
• Secondary (2°) Amines: They have two alkyl or aromatic substituents attached to the nitrogen atom.
• Tertiary (3°) Amines: They have three alkyl or aromatic substituents attached to the nitrogen atom.

In the textbook exercise, the focus is on identifying a 3° amine, which is triethylamine (B). Each ethyl group counts as a separate substituent, totaling three, and hence classifying it as a tertiary amine.

JEE MAIN AND ADVANCED Preparation Strategies

Preparing for prestigious exams like the JEE Main and Advanced requires a strategic approach towards understanding and mastering various subjects, including organic chemistry. Here are a few tips:

• Understand the Concepts: Firstly, have a strong grasp of basic concepts. Don't just memorize; understand the 'why' behind processes.
• Practice Regularly: Solve as many problems as you can, especially from previous years' papers and mock tests to familiarize yourself with the exam pattern.
• Time Management: Learn to manage your time effectively both during preparation and in the actual exam.
• Revision: Repeatedly review important concepts and problem-solving strategies.

Knowing how to identify the degree of amines, as discussed in the textbook exercise, exemplifies the type of knowledge that is crucial for doing well in these examinations.