Question

Passing two moles of acetylene and one mole of hydrogen cyanide through a red hot tube yields (1) pyrole (2) pyridine (3) ethyl amine (4) diethyl amine

Short answer

The product is pyridine.

Step-by-step solution

Identify reactants

The given reactants are two moles of acetylene \((C_2H_2)\) and one mole of hydrogen cyanide \((HCN)\).

Determine the conditions

The reaction occurs in a red-hot tube, which suggests a high-temperature reaction that may involve molecular rearrangements or coupling.

Analyze potential products

Under the provided conditions, consider the structures that these reactants can form. Acetylene can act as a building block, and when combined with hydrogen cyanide, the nitrogen containing product is likely to be formed.

Reaction Mechanism

Rearranging the given molecules under red-hot conditions, acetylene \((C_2H_2) \) and hydrogen cyanide \((HCN)\) can form pyridine \((C_5H_5N)\). Pyridine is a six-membered aromatic ring with one nitrogen atom substituting a carbon atom in the benzene ring.

Select the correct product

Identify 'pyridine' from the given options.

Key concepts

headline of the respective core concept

Acetylene is an organic compound with the formula \(C_2H_2\). It is a colorless gas and the simplest alkyne, characterized by carbon-carbon triple bonds. Acetylene is highly reactive and can participate in a variety of chemical reactions, making it a crucial building block in organic chemistry.

When acetylene is exposed to high temperatures, such as in a red-hot tube, its high reactivity can lead to significant molecular transformations.

Some crucial reactions of acetylene include:

• Substitution reactions, where the triple bond interacts with other molecules to form new products
• Polymerization, where multiple acetylene molecules combine to form larger compounds
• Coupling reactions, where acetylene bonds with different chemical species, such as cyanides, to form more complex organic structures

Understanding these reactions helps in synthesizing essential compounds like pyridine by utilizing acetylene's versatile reactive nature.

headline of the respective core concept

Pyridine is a fundamental nitrogen-containing heterocycle with the chemical formula \(C_5H_5N\). It is similar to benzene but with one nitrogen atom replacing one of the carbon atoms in the six-membered ring. This alteration imparts unique properties to pyridine, making it an important molecule in both organic synthesis and chemical industries.

Pyridine formation involves a series of steps and careful control of reaction conditions. When acetylene \(C_2H_2\) and hydrogen cyanide \(HCN\) are passed through a red-hot tube, the thermal energy facilitates the molecular rearrangement necessary to form pyridine. The high temperatures enable:

• Dehydrogenation, which helps in the removal of hydrogen atoms from the reactants
• Coupling, allowing acetylene to bond with hydrogen cyanide
• Ring formation, where the rearranged molecules form a stable aromatic structure with a nitrogen atom

Consequently, pyridine is obtained, exemplifying the importance of high-temperature reactions in synthesizing specialized organic compounds.

headline of the respective core concept

High-temperature reactions are a category of chemical reactions that occur at elevated temperatures, typically several hundred degrees Celsius. These conditions can significantly change the behavior of molecules, leading to unique and otherwise unattainable products.

In the context of the given exercise, the high-temperature reaction is essential for converting acetylene and hydrogen cyanide into pyridine.

Some key aspects of high-temperature reactions include:

• Increased kinetic energy of molecules, facilitating the breaking and formation of bonds
• Enhanced reaction rates, making it possible for new products to form quickly
• Thermal energy acting as a driving force for molecular rearrangements and synthesis

High-temperature reactions are especially crucial in organic chemistry for reactions that require significant energy input, such as synthesizing aromatic compounds, polymer formation, and complex molecular transformations, exemplified by the creation of pyridine from acetylene and hydrogen cyanide.