The major product formed in the following reaction is
The Correct Option is B
Approach Solution - 1
The Birch reduction is a process in which alkynes react with alkali metals (such as sodium, Na) in liquid ammonia (NH3) to produce trans-alkenes.
This reduction specifically targets internal alkynes, causing them to form trans-alkenes. Terminal alkynes, however, do not undergo this reduction and remain unaffected by the reaction.
Step 2: The Reaction Mechanism
When an alkyne undergoes Birch reduction, the alkali metal (sodium) donates electrons to the alkyne, resulting in the formation of a radical anion. This species reacts with ammonia to form a trans-alkene.
This reduction is selective and works primarily for internal alkynes, converting them to trans-alkenes. Terminal alkynes do not participate in this reaction and remain unchanged.
Step 3: Key Feature of the Reaction
The key characteristic of Birch reduction is the formation of **trans-alkenes** from internal alkynes. This transformation does not occur with terminal alkynes, making them unreactive under these conditions.
Step 4: Conclusion
Option (B) correctly describes this characteristic behavior of alkynes under Birch reduction conditions. It specifies that alkynes undergo Birch reduction in liquid ammonia to form trans-alkenes, while terminal alkynes do not undergo this reduction.
It is a case of Birch reduction. Alkynes on reaction with alkali metal in liq. NH3 gives trans-alkene. But terminal alkynes do not get reduced.
The correct answer is option (B):
Approach Solution -2
Option (B) states that alkynes undergo Birch reduction in liquid ammonia to form trans-alkenes, but terminal alkynes do not undergo this reduction. This succinctly summarizes the process known as Birch reduction, where alkynes react with alkali metals in liquid ammonia to produce trans-alkenes, except for terminal alkynes, which remain unaffected by this reaction. Therefore, option (B) accurately describes the characteristic behavior of alkynes under Birch reduction conditions.
Top Questions on introduction to organic chemistry
- What is the IUPAC name of CH$_3$CH(OH)CH$_3$?
- BITSAT - 2025
- Chemistry
- introduction to organic chemistry
- Which of the following represents the correct IUPAC name for \( \text{CH}_3\text{CH}_2\text{OH} \)?
- MHT CET - 2025
- Chemistry
- introduction to organic chemistry
- Which of the following represents the correct IUPAC name for \( \text{CH}_3\text{CH}_2\text{CH}_2\text{OH} \)?
- MHT CET - 2025
- Chemistry
- introduction to organic chemistry
- In which of the following ionic pairs, the second ion is smaller in size than the first ion?
- TS EAMCET - 2024
- Chemistry
- introduction to organic chemistry
Identify the products R and S in the reaction sequence given.
- TS EAMCET - 2024
- Chemistry
- introduction to organic chemistry
Questions Asked in JEE Advanced exam
- The total number of real solutions of the equation $$ \theta = \tan^{-1}(2 \tan \theta) - \frac{1}{2} \sin^{-1} \left( \frac{6 \tan \theta}{9 + \tan^2 \theta} \right) $$ is
(Here, the inverse trigonometric functions $ \sin^{-1} x $ and $ \tan^{-1} x $ assume values in $[-\frac{\pi}{2}, \frac{\pi}{2}]$ and $(-\frac{\pi}{2}, \frac{\pi}{2})$, respectively.)- JEE Advanced - 2025
- Inverse Trigonometric Functions
Let $ \mathbb{R} $ denote the set of all real numbers. Then the area of the region $$ \left\{ (x, y) \in \mathbb{R} \times \mathbb{R} : x > 0, y > \frac{1}{x},\ 5x - 4y - 1 > 0,\ 4x + 4y - 17 < 0 \right\} $$ is
- JEE Advanced - 2025
- Coordinate Geometry
The center of a disk of radius $ r $ and mass $ m $ is attached to a spring of spring constant $ k $, inside a ring of radius $ R>r $ as shown in the figure. The other end of the spring is attached on the periphery of the ring. Both the ring and the disk are in the same vertical plane. The disk can only roll along the inside periphery of the ring, without slipping. The spring can only be stretched or compressed along the periphery of the ring, following Hooke’s law. In equilibrium, the disk is at the bottom of the ring. Assuming small displacement of the disc, the time period of oscillation of center of mass of the disk is written as $ T = \frac{2\pi}{\omega} $. The correct expression for $ \omega $ is ( $ g $ is the acceleration due to gravity):
- JEE Advanced - 2025
- Waves and Oscillations
- Consider the vectors $$ \vec{x} = \hat{i} + 2\hat{j} + 3\hat{k},\quad \vec{y} = 2\hat{i} + 3\hat{j} + \hat{k},\quad \vec{z} = 3\hat{i} + \hat{j} + 2\hat{k}. $$ For two distinct positive real numbers $ \alpha $ and $ \beta $, define $$ \vec{X} = \alpha \vec{x} + \beta \vec{y} - \vec{z},\quad \vec{Y} = \alpha \vec{y} + \beta \vec{z} - \vec{x},\quad \vec{Z} = \alpha \vec{z} + \beta \vec{x} - \vec{y}. $$ If the vectors $ \vec{X}, \vec{Y}, \vec{Z} $ lie in a plane, then the value of $ \alpha + \beta - 3 $ is ________.
- If $$ \alpha = \int_{\frac{1}{2}}^{2} \frac{\tan^{-1} x}{2x^2 - 3x + 2} \, dx, $$ then the value of $ \sqrt{7} \tan \left( \frac{2\alpha \sqrt{7}}{\pi} \right) $ is.
(Here, the inverse trigonometric function $ \tan^{-1} x $ assumes values in $ \left( -\frac{\pi}{2}, \frac{\pi}{2} \right) $.)- JEE Advanced - 2025
- Integral Calculus
Concepts Used:
Introduction to Organic Chemistry
Organic chemistry is the branch of chemistry that involves the scientific study of organic compounds. Organic chemistry primarily deals with the structure and chemical composition of organic compounds, the physical and chemical properties of organic compounds, and the chemical reactions undergone by these compounds.
Reaction Intermediates in Organic Chemistry:
Intermediates can be understood as the first product of a consecutive reaction. For example, in a chemical reaction, if A→B and B→C, then, B can be said to be the intermediate for reaction A→C. The reactions in organic chemistry occur via the formation of these intermediates.
Reagents in Organic Chemistry:
Reagents are the chemicals that we add to bring about a specific change to an organic molecule. Any general reaction in organic chemistry can be written as:
Substrate + Reagent → Product
Where the substrate is an organic molecule to which we add the reagent. Based on the ability to either donate or abstract electrons, the reagents can be classified as:
- Electrophiles
- Nucleophiles