The main difference between straight and branched chain hydrocarbons is that straight-chain hydrocarbons have carbon atoms arranged in a straight line, whereas branched-chain hydrocarbons have a carbon backbone that contains one or more branches attached to them.
Hydrocarbons are a class of organic compounds composed only of the elements carbon and hydrogen. Here, the carbon atom forms the framework of the molecule, and hydrogen atoms are attached to them in many different configurations. Depending on the structure of the molecule, hydrocarbons can be divided into two main types as straight chain hydrocarbons and branched chain hydrocarbons. Hydrocarbons are the main constituents of natural gas and petroleum. Their applications are seen in fuel, lubricants, solvents, plastics, heating, and refrigerants.
Key Areas Covered
1. What are Straight-Chain Hydrocarbons
– Definition, Structure, Features
2. What are Branched-Chain Hydrocarbons
– Definition, Structure, Features
3. Difference Between Straight and Branched Chain Hydrocarbons
– Comparison of Key Differences
Key Terms
Straight-Chain Hydrocarbons, Branched-Chain Hydrocarbons
What are Straight-Chain Hydrocarbons
Straight-chain hydrocarbons are a type of hydrocarbon that contains only a single bond between carbon atoms where the remaining valencies are filled with hydrogen atoms. This gives a linear, unbranched chain structure. Straight-chain hydrocarbons are a class of organic compounds with many applications – as a fuel, lubricant, chemical feedstock, cleaning agents, etc.
The simplest hydrocarbon is methane (CH4), which has one carbon atom and four hydrogen atoms attached to the carbon atom. As the number of carbon atoms increases, their physical and chemical properties, such as the boiling point and melting point, change accordingly. The boiling point of straight-chain hydrocarbons is higher than that of branched-chain hydrocarbons. This is because of the closer packing of the molecules; hence more interactions are allowed in the straight-chain hydrocarbons.
Another property of straight-chain hydrocarbons is their reactivity. Because of the presence of single bonds, straight-chain hydrocarbons are relatively unreactive under normal conditions. But they can undergo combustion reactions with oxygen. Straight-chain hydrocarbons are more soluble in water than branched-chain hydrocarbons.
What are Branched Chain Hydrocarbons
Branched-chain hydrocarbons are hydrocarbons that contain one or more branches of carbon atoms attached to the main carbon chain. The length and the configuration of these branches can vary. The branches alter the intermolecular forces between molecules, which results in changes in physical properties such as boiling point, melting point, and solubility. Branched-chain hydrocarbons have lower boiling points and melting points than straight-chain hydrocarbons. This is because branch chains interfere with the formation of intermolecular forces between the molecules.
Another property of branched-chain hydrocarbons is their reactivity. The branching structure makes them less reactive than straight-chain hydrocarbons under normal conditions. But they still participate in reactions such as combustion, halogenation, and hydrogenation. In addition, branched-chain hydrocarbons have a lower viscosity than straight-chain hydrocarbons.
There are many applications of branched-chain hydrocarbons. They are used as fuels, lubricants, chemical feedstocks, and refrigerants.
Difference Between Straight and Branched Chain Hydrocarbons
Definition
Straight-chain hydrocarbons have carbon atoms arranged in a straight line, whereas branched-chain hydrocarbons have a carbon backbone that contains one or more branches attached to them.
Boiling Point and Melting Points
Branched-chain hydrocarbons have lower boiling points and melting points than straight-chain hydrocarbons.
Reactivity
Branched-chain hydrocarbons are less reactive than straight-chain hydrocarbons.
Solubility
Straight-chain hydrocarbons are more soluble in water than branched-chain hydrocarbons.
Viscosity
Branched-chain hydrocarbons have a lower viscosity than straight-chain hydrocarbons.
Conclusion
Hydrocarbons are a class of organic compounds composed only of carbon and hydrogen. The carbon atom forms the framework of the molecule, and hydrogen atoms are attached to them. Depending on the structure of the molecule, hydrocarbons can be divided into two main types; they are straight-chain hydrocarbons and branched-chain hydrocarbons. The main difference between straight and branched chain hydrocarbons is that straight-chain hydrocarbons have carbon atoms arranged in a straight line, whereas branched-chain hydrocarbons have a carbon backbone that contains one or more branches attached to it.
Reference:
1. “Branched Hydrocarbons.” Introductionary Chemistry. Open Text.
2. “Straight-chain hydrocarbon.” Encyclopedia Britannica.
Image Courtesy:
1. “Alkane 4 structure” By 1840460mahesh – Own work (CC BY-SA 4.0) via Commons Wikimedia
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