Draw the structural formulas of (a) \(2,2,4\) trimethylpentane, \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{COH}_{2} \mathrm{CH}\left(\mathrm{CH}_{3}\right)_{2}\), which is also called isooctane and is used to raise the octane rating of gasolinc; (b) 2 -methyl-1-propanol, which is commonly sold as isobutyl alcohol and used to make fruit flavorings.

When tackling the structure of isooctane, it's essential to start with the basics. Isooctane, known in the chemistry world as 2,2,4-trimethylpentane, is more than just a mouthful—it's a fascinating compound with significant applications.

Isooctane's claim to fame comes from its role in boosting gasoline's octane rating, which essentually means it helps fuel burn more efficiently in engines and reduces knocking. Its structural formula reveals that isooctane is a branched chain hydrocarbon, which means it includes a main carbon chain with additional 'branches' or methyl groups off the sides.

Visualize a carbon chain five atoms long this is your pentane backbone. From this chain, two methyl groups spring off the second carbon atom, with one more making an appearance on the fourth carbon. Sketching this out, you'll see why it's referred to as a branched isomer; the molecule has a distinct shape that resembles a tree with branches. This configuration is pivotal as it imparts the molecule with certain thermodynamic properties, such as a relatively high octane number.

Diving deeper into the structure of 2,2,4-trimethylpentane, this molecule showcases the beauty of organic chemistry nomenclature. The '2,2,4' tuple is a roadmap directing you to the location of each methyl group on the primary pentane chain. A 'methyl' group is a single carbon atom bound to three hydrogen atoms, illustrated as CH3 in molecular formulas.

In creating a visual representation, a straight-line structure begins by drawing five carbon atoms linked in a row—our pentane core. Two additional CH3 groups are added to the second carbon atom, while one is added to the fourth carbon. These substitutions on the parent chain are what give 2,2,4-trimethylpentane its distinctive architecture and name. This structure results in a molecule with 8 carbon atoms in total, crafted into a unique yet symmetrical form that marks the essence of isooctane.

Intricacies of organic compounds are exemplified when examining 2-methyl-1-propanol. This molecule is an alcohol, as evidenced by the presence of a hydroxyl group (OH), a duo of oxygen and hydrogen that's keen on making friendships with other molecules. What sets 2-methyl-1-propanol apart is its location of its constituents on the carbon chain.

Breaking down the name, 'propanol' indicates a three-carbon backbone with an alcohol group. The prefix '2-methyl' signifies an extra carbon unit, a methyl group, connected to the middle (second) carbon. Then, an OH group is bonded to the first carbon, earning the '1' in 1-propanol. When drawn, this structure shouts its alcohol nature while simultaneously showcasing the added complexity a methyl group introduces. Commonly recognized as isobutyl alcohol, 2-methyl-1-propanol is a key ingredient in fruity flavor concoctions, highlighting its versatility beyond mere structural intrigue.

Isobutyl alcohol, while sharing similar roots with its close relative isooctane, is a distinct molecule with its own set of properties and uses. Unlike isooctane, this compound is an alcohol, which is easy to remember thanks to the 'ol' ending in its name, denoting the presence of a hydroxyl group.

Also recognized by its more formal name, 2-methyl-1-propanol, isobutyl alcohol is often employed in the creation of fragrances and fruit flavorings, owed to its moderate volatility and ability to interact with other chemicals to produce desired aromas and tastes. In its structural formula, we see a three-carbon chain with a hydroxyl (OH) group attached at one end, which is classified as the alcohol functional group, and a methyl group attached to the second carbon, giving it the 'isobutyl' identity. This structure is central to the characteristics that define isobutyl alcohol's physical and chemical behavior. Drawing this out can aid in grasping how such a small change in structure, adding a simple methyl group, can transform propanol into the versatile isobutyl alcohol.