Chapter 10: Problem 27
Classify the following molecules according to their functional groups. The
possibilities are alcohol, ether, ketone, carboxylic acid, or amine.
a.
\(\mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{O}-\mathrm{CH}_{2}-\mathrm{CH}_{3}\)
b.
Short Answer
Expert verified
a: ether, b: alcohol, c: ketone, d: carboxylic acid, e: amine
Step by step solution
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Ether Functional Group
Ethers are a type of functional group characterized by an oxygen atom connected to two alkyl or aryl groups. This gives ethers the general formula \(\text{R-O-R'}\). In the molecule \( \text{CH}_{3}-\text{CH}_{2}-\text{O}-\text{CH}_{2}-\text{CH}_{3} \), the oxygen atom is bonded to two ethyl groups (\text{CH}_{2}-\text{CH}_{3}). This pattern is what defines an ether.
Here are some properties of ether functional groups:
Here are some properties of ether functional groups:
- The oxygen atom in ethers is generally more electronegative than the carbon atoms, which affects the electron distribution.
- Ethers are typically less reactive than alcohols due to the lack of a hydrogen atom attached to the oxygen.
- They are often used as solvents in organic reactions due to their relatively inert nature.
Alcohol Functional Group
Alcohols contain an \(\text{-OH}\) (hydroxyl) group attached to a carbon atom. The general formula for an alcohol is \(\text{R-OH}\), where \(\text{R}\) represents an alkyl group. In the translated molecule \( \text{CH}_{3}-\text{CH}_{2}-\text{CH}(-\text{CH}_{3})-\text{OH} \), there is one hydroxyl group (\text{-OH}) making it an alcohol.
Some common features of alcohols include:
Some common features of alcohols include:
- The presence of the hydroxyl group makes alcohols polar and capable of hydrogen bonding.
- Alcohols can engage in both substitution and elimination reactions due to the \(\text{-OH}\) group.
- They are commonly used in beverages, as disinfectants, and as solvents in chemical industries.
Ketone Functional Group
Ketones include a carbonyl group (\text{C=O}) within the carbon chain. Their general formula is \(\text{R-CO-R'}\). For the molecule \( \text{CH}_{3}-\text{CH}_{2}-\text{C}(=O)-\text{CH}_{2}-\text{CH}_{3} \), the carbonyl group is bound to two carbon atoms within the chain, identifying it as a ketone.
Important aspects of ketones include:
Important aspects of ketones include:
- Ketones cannot form hydrogen bonds with themselves, making them less polar than alcohols.
- The carbonyl group is highly reactive because the carbon is electrophilic.
- Ketones are often used in perfumes and as solvents due to their distinct smell.
Carboxylic Acid Functional Group
Carboxylic acids have a carboxyl group (\text{COOH}) at the end of a carbon chain. The general formula is \(\text{R-COOH}\). In \( \text{CH}_{3}-\text{CH}_{2}-\text{CH}_{2}-\text{COOH} \), the carboxyl group is present, classifying it as a carboxylic acid.
Properties of carboxylic acids include:
Properties of carboxylic acids include:
- They are acidic because they can donate a proton (H+) from the carboxyl group.
- They often participate in hydrogen bonding, which affects their boiling and melting points.
- Carboxylic acids are commonly found in foods and fragrances, and are used in the production of pharmaceuticals.
Amine Functional Group
Amines feature an amino group (\text{-NH}_{2}) attached to a carbon atom. The general formula is \( \text{R-NH}_2 \), where \(\text{R}\) is an alkyl group. In the molecule \( \text{CH}_{3}-\text{CH}_{2}-\text{NH}_{2} \), the nitrogen atom is bonded to an ethyl group, indicating it is an amine.
Key characteristics of amines include:
Key characteristics of amines include:
- Amines are basic due to the lone pair of electrons on the nitrogen, which can accept a proton.
- They are soluble in water and can form hydrogen bonds.
- Amines are vital in biology and are found in amino acids, proteins, and DNA.
