Question

How many deuterium atoms would present in product obtained after treatment of ' \(\mathrm{X}\) ' with \(\mathrm{OD}^{-} / \mathrm{D}_{2} \mathrm{O}\) for a long time? (A) 5 (B) 6 (C) 7 (D) 9

Short answer

Since the compound 'X' is not provided, we cannot determine the specific number of deuterium atoms resulting from the treatment with \(\mathrm{OD}^{-} / \mathrm{D}_{2} \mathrm{O}\). If 'X' were provided, we would identify the acidic protons, predict the number of deuterium atoms after treatment, and choose the option (5, 6, 7, or 9) that best matches our calculation.

Step-by-step solution

Identify acidic protons in 'X'

Consider a hypothetical compound 'X' containing the following types of acidic protons: 1. Hydrogen atoms attached to oxygen, nitrogen, or similar electronegative atoms. 2. Hydrogen atoms in an alkene (like in enols). 3. Hydrogen atoms adjacent to carbonyl (C=O) groups (like in enols and enolates). 4. Hydrogen atoms in acidic aliphatic C-H bonds (like in terminal alkynes).

Determine the number of deuterium atoms after treatment

Once we've identified the number of acidic protons in 'X', we can determine how many of these protons would be exchanged with deuterium atoms when treated with \(\mathrm{OD}^{-} / \mathrm{D}_{2} \mathrm{O}\) for a long time. Suppose our hypothetical compound 'X' has Y number of acidic protons. After treatment with \(\mathrm{OD}^{-} / \mathrm{D}_{2} \mathrm{O}\) for a long time, all these protons are likely to be exchanged with deuterium atoms, and the final number of deuterium atoms in the product will be equal to Y.

Compare the obtained number of deuterium atoms with given choices

Now, compare the determined number of deuterium atoms (Y) in the final product with the given choices A, B, C, and D. The correct choice should be the one that corresponds to the number of deuterium atoms we've calculated - either 5, 6, 7, or 9. In this example, since the actual compound 'X' is not provided, we cannot determine the specific number of deuterium atoms resulting from the treatment. If 'X' were provided, we would follow the steps above to identify the acidic protons, predict the number of deuterium atoms after treatment, and choose the option that best matches our calculation.

Key concepts

Isotopic Labeling with Deuterium

Isotopic labeling with deuterium is a powerful technique used in organic chemistry to investigate reaction mechanisms and study molecular behaviors.

Deuterium, denoted as 'D', is a stable isotope of hydrogen with one neutron, making it twice as heavy as the more common hydrogen isotope, which has no neutrons. During isotopic labeling, chemists replace specific hydrogen atoms in a molecule with deuterium to observe how these atoms affect the properties and reactions of the molecule.

The process often involves using deuterated reagents, such as deuterium oxide (D2O) and deuterium-labeled hydroxide (OD-), to facilitate the exchange. In this type of exchange reaction, the molecule absorbs the deuterium to replace the acidic protons, those more easily removed due to their attachment to electronegative atoms or within certain functional groups.

It's crucial to note that only acidic hydrogen atoms are likely to be replaced by deuterium. This specificity is utilized to learn about the presence and location of acidic protons in a molecule, sometimes revealing subtle details about a compound’s structure.

Exchange Reactions in Organic Chemistry

Exchange reactions in organic chemistry refer to processes where specific atoms in a compound are replaced by other atoms or groups without altering the compound's primary structure.

A common example involves exchanging protons (H+) with deuterium (D+), as explored in isotopic labeling. The process doesn't change the molecular skeleton but switches the isotopic form of an atom. For such a reaction to occur, the original atom—usually a proton—must be sufficiently acidic to be removed by a base, such as OD- in a deuterated solution like D2O.

These reactions are not only a tool for structural analysis but also play a key role in elucidating reaction mechanisms. By observing which protons are exchanged in a molecule, chemists can determine which positions in the molecule are most reactive or involved in a given process.

Stereochemistry in JEE Chemistry

Stereochemistry is a sub-discipline of chemistry that involves the study of the three-dimensional arrangement of atoms within molecules and how this arrangement affects chemical reactions and properties.

This field is particularly crucial for JEE Chemistry aspirants, as it forms an integral part of the syllabus for both JEE Main and Advanced examinations. Understanding concepts such as chirality, optical isomerism, and conformational isomers is essential to solving complex problems presented in these exams.

Stereochemistry not only influences physical and chemical properties of substances but also plays a significant role in the biological activity of molecules. Aspirants must therefore develop a strong grasp of spatial concepts and the ability to analyze molecules from different perspectives to excel in this topic. Questions often require students to predict the outcomes of reactions or to determine the stereochemical relationship between different molecules.

JEE Main and Advanced Preparation

Preparation for the JEE Main and Advanced examinations requires focused study and a deep understanding of a range of topics in Physics, Chemistry, and Mathematics.

Aspiring students need to develop a structured approach to cover the vast syllabus, which encompasses Stoichiometry, Thermodynamics, Organic Chemistry - including topics like isotopic labeling and stereochemistry - as well as other major branches of science.

A combination of conceptual learning, problem-solving, and mock tests is pivotal for success. Regularly practicing textbook exercises, such as those involving the identification of acidic protons and the application of isotopic labeling, helps in reinforcing the concepts. It is also vital for students to work on their time management skills and exam strategies to efficiently tackle the type of questions presented in JEE Main and Advanced.