Name each of the following compounds as an unbranched alkane: (a) \(\mathrm{C}_{9} \mathrm{H}_{20}\); (b) \(\mathrm{C}_{6} \mathrm{H}_{14}\); (c) \(\mathrm{C}_{11} \mathrm{H}_{24}\); (d) \(\mathrm{C}_{12} \mathrm{H}_{26}\).

Organic chemistry is a sub-discipline within chemistry that involves the scientific study of the structure, properties, composition, reactions, and synthesis of organic compounds primarily made of carbon atoms. In the context of organic chemistry, hydrocarbons are of paramount importance.

Hydrocarbon compounds, such as alkanes, are composed solely of carbon(C) and hydrogen(H) atoms. They can be structured in various forms including linear and branched chains, rings, and more complex structures. Alkanes, specifically, are the simplest type of hydrocarbon and are referred to as saturated hydrocarbons because they contain only single bonds, which results in a maximal number of hydrogen atoms attached to the carbon chain.

To understand alkanes, one must be acquainted with their general formula, which plays a crucial role in deducing the names of the compounds under investigation in exercises such as the one provided.

A hydrocarbon chain is a sequence of carbon atoms linked together by single or multiple bonds and flanked by hydrogen atoms. When delving into alkanes, we are dealing with hydrocarbon chains that possess only single bonds between the carbon atoms, conforming to the general formula of alkanes, which is given by \( C_nH_{2n+2} \)

Unbranched, or linear, hydrocarbon chains are those that consist of a sequence of carbon atoms connected in a straight line without any side chains or branches. The length of this chain is a determinant in the naming process of alkanes, as each length corresponds to a unique prefix that is used in the naming convention. For instance, a five-carbon alkane chain would be prefixed with 'pent-', indicating its length, and when adhering to the proper nomenclature procedures, is named as pentane.

The International Union of Pure and Applied Chemistry (IUPAC) has developed a systematic method for naming organic chemical compounds to ensure that each has a unique and universally identifiable name. This nomenclature is particularly crucial for educational purposes and in professional chemistry settings to avoid confusion.

The IUPAC naming system for alkanes consists of identifying the length of the longest continuous carbon chain and using a specific prefix that corresponds to that length. After identifying the prefix, the suffix '-ane' is then appended to indicate that the compound is an alkane. For example, the compound with the formula \( C_9H_{20} \) follows the steps outlined in the exercise: by recognizing that the longest chain has 9 carbon atoms, we use the prefix 'non-' and add the suffix '-ane', thereby naming it nonane.

Practical Examples

To further underscore this, consider the following solved examples:

• For the compound \( C_6H_{14} \), with 6 carbons, the name is hexane.
• For the compound \( C_{11}H_{24} \), with 11 carbons, the name is undecane.
• For the compound \( C_{12}H_{26} \), with 12 carbons, the name is dodecane.

Following the step-by-step solution can clarify the IUPAC naming process for students and can be applied to practice problems to solidify understanding.