Question

The number of structural isomers for \(\mathrm{C}_{6} \mathrm{H}_{14}\) is (A) 3 (B) 4 (C) 5 (D) 6

Short answer

The number of structural isomers for \text{C}_{6}\text{H}_{14} is 5.

Step-by-step solution

Understand the Concept of Structural Isomers

Structural isomers are compounds with the same molecular formula but different structural formulas. This means the atoms are connected in a different order or arrangement, even though the same types of atoms are present in the same quantities.

Draw the Possible Isomers for \text{C}_{6}\text{H}_{14}

Begin by drawing the straight-chain isomer, hexane, which has all six carbon atoms in a row. Then, create branched isomers by moving one carbon atom from the main chain to create a branch and continue this process to find all unique arrangements without repeating any that are identical through rotation.

Ensure the Uniqueness of Isomers

Verify that each drawn isomer is unique and not simply a rotated version of another. Also, ensure there are no identical groups attached to the same carbon, which would not count as a new isomer.

Count the Valid Structural Isomers

After drawing and confirming the uniqueness of each structure, count the number of valid structural isomers for C6H14.

Key concepts

Understanding Isomerism

Isomerism is a fundamental concept in organic chemistry reflecting the diversity of molecular structures that can lead to entirely different physical and chemical properties. It occurs when compounds have the same molecular formula, indicating the same number and type of atoms, but the atoms are arranged in different ways. Structural isomers, specifically, vary in how their atoms are connected to each other. They are like puzzles where the pieces can be connected in multiple ways to create various images.

Students often find visualizing isomers challenging since it's not merely about changing positions but understanding the actual feasible connectivity between atoms to form stable molecules. A molecule like hexane, with a simple formula of \text{C}\(_{6}\)\text{H}\(_{14}\), can have several isomers, each with unique properties despite sharing the same chemical formula. This diversity in structural arrangement is the essence of isomerism and its significant implications in organic chemistry.

Exploring Organic Chemistry

Organic chemistry is the branch of chemistry concerned with the study of carbon-containing compounds and their reactions. Carbon's ability to form four strong covalent bonds makes it extraordinarily versatile, creating a vast array of compounds. This field of chemistry is underpinned by the concept of isomerism, which adds richness to the complexity of organic substances. It's not just about knowing the formulas, but also about understanding the three-dimensional structures and how they can influence the reactivity and interactions of molecules.

In examining a compound like hexane, students should appreciate that structural variations affect the molecule's boiling point, density, and solubility. Realizing that each isomer can have a different function in the real world, from fuels to solvents, illuminates the practical importance of this intricate branch of science.

The Versatility of Hexane

Distinguishing Hexane Isomers

Organic compounds such as hexane, which has a simple structure and is often encountered in introductory organic chemistry courses, serve as a prime example of structural isomerism. When exploring hexane isomers, students learn that all isomers have six carbon atoms, but they differ in how these carbons are arranged. This results in distinct molecules, each with a different name and set of properties, which is why it is crucial to understand how to identify and differentiate between them.

To improve comprehension, it's advisable for students to practice drawing these isomers and to explore their physical and chemical properties through experimentation when possible. This hands-on approach enhances their ability to recognize and predict how the structure of a compound can affect its behavior and uses.

Deciphering Molecular Formulas

Interpreting \text{C}\(_{6}\)\text{H}\(_{14}\)

Molecular formulas are a compact way to describe the composition of a chemical compound. They show the types and numbers of atoms present, but not how those atoms are bonded to each other. For instance, the molecular formula \text{C}\(_{6}\)\text{H}\(_{14}\) represents a compound with six carbon atoms and fourteen hydrogen atoms. However, it doesn't reveal anything about the structure of the molecule, which is where the concept of isomers becomes particularly relevant.

To grasp molecular formulas in the context of isomerism, students should practice not only writing out the molecular formula from a given structure but also drawing possible structures from a molecular formula. This skill is crucial for mastering organic chemistry and for predicting the possible arrangements and accompanying properties of molecular compounds.