Question

Draw structural formulas for the four possible alcohols with the formula \(\mathrm{C}_{4} \mathrm{H}_{10}\) O. Give the systematic name of each.

Short answer

The four alcohols are butan-1-ol, butan-2-ol, 2-methylpropan-1-ol, and 2-methylpropan-2-ol.

Step-by-step solution

Understand the Problem

The problem asks us to draw structural formulas and find the systematic names of all possible alcohols with the molecular formula \( \mathrm{C}_{4} \mathrm{H}_{10} \mathrm{O} \). Alcohols are organic compounds which contain a hydroxyl group (\(-\mathrm{OH}\)) attached to a saturated carbon atom.

Consider Different Carbon Chain Arrangements

Start by considering possible arrangements of four carbon atoms in a chain, as this will determine the base of our alcohol structures. The possible carbon skeletons are: a straight chain with four carbons and a branched chain with three carbons.

Draw and Name Butan-1-ol

Draw the first possible alcohol by attaching the hydroxyl group to the end of a straight-chain of four carbon atoms: \( \mathrm{CH}_{3}-\mathrm{CH}_2-\mathrm{CH}_2-\mathrm{CH}_2\mathrm{OH} \). The systematic name for this structure is butan-1-ol.

Draw and Name Butan-2-ol

Draw the second possible alcohol by attaching the hydroxyl group to the second carbon of the straight chain: \( \mathrm{CH}_{3}-\mathrm{CH}_2-\mathrm{CH}( ext{OH})-\mathrm{CH}_3 \). The systematic name for this structure is butan-2-ol.

Draw and Name 2-Methylpropan-1-ol

Draw the third possible alcohol by attaching the hydroxyl group to the end carbon of a branched chain: \( \mathrm{(CH}_{3})_2\mathrm{CH}-\mathrm{CH}_2\mathrm{OH} \). The systematic name for this structure is 2-methylpropan-1-ol.

Draw and Name 2-Methylpropan-2-ol

Draw the fourth possible alcohol by attaching the hydroxyl group to the central carbon of a branched chain: \( \mathrm{(CH}_{3})_3\mathrm{C}\text{OH} \). The systematic name for this structure is 2-methylpropan-2-ol.

Key concepts

Structural Formulas

Structural formulas are a fundamental way to represent molecules, showing how atoms are connected within the molecule. It's like a roadmap of the molecule's structure, providing a visual way to understand how the different atoms are bonded together. Here's what you need to know:

• Carbon Skeleton: The carbon atoms form the backbone or skeleton of organic molecules. In our exercise problem, we are dealing with alcohols that have four carbon atoms.
• Straight and Branched Chains: The arrangement of carbon atoms can vary. A straight chain is when carbon atoms are in a continuous line. A branched chain involves a tree-like structure, where some carbon atoms are not connected in a single straight line.
• Attachments: Beyond the carbon skeleton, hydrogen atoms and hydroxyl groups (OH) attach to complete the molecule.

These structural details help chemists understand the properties and reactions of the molecule. Different arrangements can lead to different types of molecules even with the same molecular formula, as seen in isomers.

Systematic Naming

In organic chemistry, systematic naming is a method used to provide a unique name to each compound. This ensures consistency and clarity across scientific communication. For alcohols, the International Union of Pure and Applied Chemistry (IUPAC) provides the naming guidelines:

• Identifying the Longest Carbon Chain: Start by locating the longest continuous chain of carbon atoms in the molecule, which forms the base name of the alcohol.
• Number the Chain: The carbon chain is numbered to minimize the position number of the hydroxyl group, reflecting its location in the name.
• Add Prefixes for Alkyl Groups: If there are any side chains (alkyl groups), their position on the carbon chain and name are added before the base name.
• End with '-ol': Replace the '-e' in the alkane name with '-ol' to indicate the presence of a hydroxyl group. For example, 'butane' becomes 'butanol.' Adding numbers indicates which carbon the hydroxyl group is attached to, such as in butan-1-ol or butan-2-ol.

These rules ensure each compound has a precise name that conveys structural information.

Organic Chemistry

Organic chemistry is the branch of chemistry that studies the structure, properties, composition, reactions, and synthesis of carbon-containing compounds. Within this vast field, alcohols are a prominent class of compounds:

• Carbon Atoms: As the building blocks, carbon atoms form stable chains and rings, which can be straight or branched, and play a central role in organic molecules.
• Functional Groups: These are specific groupings of atoms within molecules that are responsible for characteristic reactions of those molecules. In alcohols, the functional group is the hydroxyl group (OH).
• Versatility of Organic Compounds: The presence of carbon allows for a wide variety of compounds with diverse properties and functions, which makes organic chemistry incredibly important for fields like biology, medicine, and materials science.

Organic chemistry not only explains the diversity of life’s molecular interactions, but it also allows us to synthesize new materials and drugs that can improve quality of life.

Hydroxyl Group

The hydroxyl group, represented as -OH, is fundamental in the chemistry of alcohols. It is the defining feature of an alcohol, distinguishing it from other types of organic compounds. Here's how the hydroxyl group influences alcohols:

• Polar Nature: The hydroxyl group is polar due to the oxygen atom being more electronegative than hydrogen. This gives alcohols the ability to form hydrogen bonds, affecting their boiling and melting points.
• Reactivity: The presence of the hydroxyl group means that alcohols can participate in a variety of chemical reactions, such as oxidation and substitution, which can convert them into other useful organic compounds.
• Solubility: The polar nature of the hydroxyl group also enhances the solubility of alcohols in water, which is important for their use in both industrial and biological processes.

Understanding the hydroxyl group is crucial for grasping the properties and reactivity of alcohols and their role in organic chemistry.