Question

What is an alkyne? What structural feature characterizes alkynes? Give the general formula for alkynes.

Short answer

An alkyne is an unsaturated hydrocarbon containing a carbon-carbon triple bond (C≡C). The triple bond, consisting of one sigma bond and two pi bonds with a linear molecular shape, characterizes alkynes. The general formula for alkynes is CnH2n-2, where n represents the number of carbon atoms in the molecule.

Step-by-step solution

Definition of Alkynes

Alkynes are a class of organic compounds containing a carbon-carbon triple bond. They are unsaturated hydrocarbons that consist of hydrogen and carbon atoms.

Structural Feature of Alkynes

The structural feature that characterizes alkynes is the carbon-carbon triple bond (C≡C). In this bond, there is one sigma bond and two pi bonds between the two carbon atoms. The bond angle around the carbon atoms involved in the triple bond is approximately 180 degrees, which results in a linear molecular shape.

General Formula for Alkynes

The general formula for alkynes follows the format CnH2n-2, where n is the number of carbon atoms in the molecule. This formula indicates that alkynes have two fewer hydrogen atoms than the equivalent alkene structure.

Key concepts

Organic Compounds

Organic compounds are a fascinating and diverse category of chemical substances that play a crucial role in many aspects of life and industry. These compounds are primarily made up of carbon atoms, often in combination with hydrogen, oxygen, nitrogen, and other elements.
One of the main characteristics of organic compounds is their ability to form long chains and complex structures due to carbon’s unique bonding properties.

• Carbon atoms can form stable covalent bonds with other elements, particularly other carbon atoms, resulting in a wide variety of structures.
• This variety in structure allows organic compounds to fulfill many roles, from serving as fuels to forming the basis of living organisms.

In the realm of organic chemistry, understanding these compounds' structures and formulas is essential in predicting their reactivity and properties. Organic compounds like alkynes have distinct features, making them a subject of interest for students and educators alike.

Carbon-Carbon Triple Bond

The carbon-carbon triple bond is a distinctive feature of alkynes, a type of organic compound. This type of bond involves three pairs of shared electrons between two carbon atoms, creating a very strong connection.
What's intriguing about a triple bond is its composition:

• It includes one sigma (\(σ\)) bond which is quite strong and formed by the head-on overlap of atomic orbitals.
• Additionally, there are two pi (\(π\)) bonds formed by the side-by-side overlap of p orbitals. These pi bonds offer flexibility in chemical reactions.

The presence of the carbon-carbon triple bond gives alkynes unique geometric and chemical properties. The straight-line bond angle is approximately 180 degrees, leading to a linear shape around the bond. This linearity contributes to alkynes' unique characteristics and reactions compared to other hydrocarbons.

Unsaturated Hydrocarbons

Unsaturated hydrocarbons are a crucial part of organic chemistry, known for containing double or triple bonds between carbon atoms, making them more reactive than saturated hydrocarbons. These unsaturated bonds can be avenues for reactions, such as polymerization or addition reactions.
Alkynes are one kind of unsaturated hydrocarbon characterized by their carbon-carbon triple bond.

• This triple bond means alkynes have fewer hydrogen atoms compared to their saturated counterparts like alkanes.
• Their general formula, \(C_nH_{2n-2}\), highlights this hydrogen deficiency.

The unsaturated nature of alkynes makes them valuable in various synthetic processes and reactions in organic chemistry, such as the production of polymers, pharmaceuticals, and other complex molecules.