Question

Which of the following compounds are alcohols? (a) \(\mathrm{CH}_{3} \mathrm{CHO}\) (b) \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{C}(\mathrm{OH}) \mathrm{CH}_{3}\) (c) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{COCH}_{3}\) (d) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OCH}_{2} \mathrm{CH}_{3}\) (e) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{OH}\)

Short answer

Compounds (b) and (e) are alcohols.

Step-by-step solution

Identify the functional group for compound (a)

Compound (a) is \(\mathrm{CH}_{3} \mathrm{CHO}\). There is no hydroxyl group (-OH) attached to the carbon atom, so it is not an alcohol.

Identify the functional group for compound (b)

Compound (b) is \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{C}(\mathrm{OH}) \mathrm{CH}_{3}\). Here we see that the hydroxyl group (-OH) is attached to a carbon atom, which defines it as an alcohol.

Identify the functional group for compound (c)

Compound (c) is \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{COCH}_{3}\). There is no -OH group attached to a carbon atom, thus it isn't an alcohol.

Identify the functional group for compound (d)

Compound (d) is \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OCH}_{2} \mathrm{CH}_{3}\). There is an oxygen atom in the molecule, but no hydroxyl group (-OH) attached directly to a carbon atom, which means it is not an alcohol.

Identify the functional group for compound (e)

Compound (e) is \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{OH}\). The molecule contains a hydroxyl group (-OH) attached to a carbon atom, hence it is an alcohol.

Key concepts

Organic Chemistry

Organic chemistry is the branch of chemistry that deals with carbon-containing compounds, which are the basis of all living organisms. In organic chemistry, we study the structure, properties, and reactions of organic molecules. These molecules are diverse in terms of the types of atoms and the way atoms are connected, providing an array of substances with unique properties.

For example, when examining substances to determine whether they are alcohols, we look for a specific type of organic molecule that contains one or more hydroxyl groups. The ability to identify different organic compounds, such as alcohols, is foundational in organic chemistry and has profound implications in fields ranging from pharmacology to material sciences.

Functional Groups

In the realm of organic chemistry, functional groups are specific atoms or groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. They are the reactive parts of the molecule and dictate how a compound will behave when it interacts with other substances.

Consequently, identifying functional groups is key to understanding organic chemistry. Not only do they define the structure of the compound, but they also play a pivotal role in determining its physical and chemical properties. For instance, knowing that a molecule contains a hydroxyl group informs chemists that the substance belongs to the alcohol class of organic compounds.

Hydroxyl Group

The hydroxyl group, represented as -OH, is one of the fundamental functional groups in organic chemistry. It consists of an oxygen atom bonded to a hydrogen atom, and this group is the defining feature of an alcohol.

When a hydroxyl group is connected to a saturated carbon atom (a carbon atom with single bonds only), the compound it forms is known as an alcohol. Different alcohols may have varied properties depending on where the hydroxyl group is located within the molecule, as well as the overall size and structure of the molecule.

Alcohols can be categorized based on the number of hydroxyl groups present and the complexity of the carbon chain they are attached to, resulting in a diverse group of compounds with both common uses in daily life, like ethanol in alcoholic beverages, and specialized applications in industry and healthcare.