Aldehydes, Ketones, Carboxylic Acids, and Esters

Comprehensive review flashcards covering IUPAC nomenclature, physical properties, chemical reactions, and notable examples of aldehydes, ketones, carboxylic acids, and esters.

What characterizes an aldehyde, and how is it named according to IUPAC nomenclature?

Aldehydes contain a carbonyl functional group at the front or end of a carbon chain. To name them, find the longest carbon chain containing the carbonyl group, drop the '-e' ending from the alkane name, and add the suffix '-al'.

What is the IUPAC name of the aldehyde shown in the structure?

2-ethylbutanal

What structural feature defines a ketone, and how is it named according to IUPAC nomenclature?

Ketones contain a carbonyl functional group positioned between two other carbon atoms. They are named by finding the longest carbon chain containing the carbonyl, dropping the '-e' ending, adding '-one', and including position numbers where needed.

What is the IUPAC name of the dione compound shown in the image?

butane-2,3-dione

How is the carbonyl group numbered in cyclic ketones, and what is the base name for an aldehyde attached directly to a benzene ring?

In cyclic ketones, the carbonyl group carbon is always assigned position number 1 (though the number 1 is not written in the name). A benzene ring with an attached aldehyde group is named benzaldehyde.

Why can aldehydes and ketones experience dipole-dipole attractions but cannot form hydrogen bonds between themselves?

The carbonyl group is polar ($\text{C}^{\delta+}=\text{O}^{\delta-}$, enabling dipole attractions), but aldehydes and ketones lack a hydrogen atom bonded directly to an oxygen atom, making intermolecular hydrogen bonding between their own molecules impossible.

How do alcohols, aldehydes/ketones, ethers, and alkanes compare in boiling point and water solubility from highest to lowest?

Alcohols > Aldehydes/Ketones > Ethers > Alkanes

What organic products result from the controlled oxidation of primary versus secondary alcohols?

The controlled oxidation of a primary ($1^\circ$) alcohol yields an aldehyde, whereas the controlled oxidation of a secondary ($2^\circ$) alcohol yields a ketone.

What are three common oxidizing agents used in organic chemistry to prepare aldehydes and ketones from alcohols?

$\text{KMnO}_4$, $\text{H}_2\text{O}_2$, and $\text{K}_2\text{Cr}_2\text{O}_7$

What reagents and conditions are required to carry out a hydrogenation reaction on an aldehyde or ketone?

Addition of $\text{H}_2$ gas under conditions of high heat, high pressure, and in the presence of a platinum ($\text{Pt}$) catalyst.

What are the practical applications or natural roles of dihydroxyacetone and heptan-2-one?

Dihydroxyacetone is used in bronzers to react with dead skin cells, while heptan-2-one produces the odour of many fruits, vegetables, and blue cheese.

What specific human pheromone compound was isolated from human sweat by researchers in Philadelphia in 1986?

Androstenone

What was observed in the twin brothers experiment evaluating the effects of human pheromones?

Even though both identical twin brothers looked exactly the same, women found the twin brother wearing the actual pheromone significantly more sexually attractive.

What functional group defines carboxylic acids, and what is its chemical formula?

Carboxylic acids contain the carboxyl functional group, represented by the formula $-\text{COOH}$, in which the two oxygen atoms are not joined to each other.

What are the rules for naming carboxylic acids under IUPAC nomenclature?

Determine the longest continuous chain of carbon atoms with the carboxyl carbon designated as carbon-1 (C#1). Drop the '-e' ending of the parent alkane name and add '-oic acid' as two separate words.

What is the IUPAC name of the dicarboxylic acid shown in the image?

butanedioic acid

What is the systematic name for an aromatic carboxylic acid consisting of a benzene ring with a carboxyl group and a chlorine substituent at carbon 3?

3-chlorobenzoic acid

How are carboxylic acids prepared from aldehydes via an oxidation reaction?

An aldehyde is reacted with an oxidizing agent ($[\text{O}]$) to produce a carboxylic acid, generating water as a side product.

Why do carboxylic acids have higher boiling and melting points than aldehydes, ketones, and alkanes of similar molar mass?

The carboxyl group is highly polar and contains both a carbonyl and a hydroxyl group, which allows carboxylic acid molecules to form extensive intermolecular hydrogen bonds with each other.

What defines fatty acids in terms of their carbon chain length?

Carboxylic acids containing $12$ to $20$ carbon atoms, typically found in the triglycerides of fats and oils.

What natural sources or household mixtures correspond to methanoic acid, ethanoic acid, and propanoic acid?

Methanoic acid is found in ant and caterpillar venom; a $5\%$ aqueous solution of ethanoic acid is vinegar; propanoic acid is found in Swiss cheese.

What biological roles or uses are associated with PABA, Niacin, and GABA?

Para-aminobenzoic acid (PABA) is used in sunscreen; Niacin is a vitamin required for growth; gamma-aminobutanoic acid (GABA) serves as a neurotransmitter in the brain.

What functional group arrangement defines an ester?

An ester contains a carbonyl group bonded directly to an oxygen atom, which is in turn bonded to another carbon chain ($\text{R-COO-R'}$).

How are the two parts of an ester named in IUPAC nomenclature?

The first part comes from the alkyl group bonded to the single-bonded oxygen atom. The second part comes from the carbon chain containing the carbonyl group, dropping '-e' and adding '-oate'.

What is the IUPAC name of the ester depicted in the image?

ethyl butanoate

What reactants, catalyst, and conditions are needed for an esterification reaction?

A carboxylic acid is reacted with an alcohol in the presence of sulfuric acid ($\text{H}_2\text{SO}_4$) and heat.

What reaction occurs during the base-catalyzed hydrolysis of an ester?

Water is added to an ester in the presence of a strong base, cleaving the ester linkage to produce a carboxylic acid and an alcohol.

Why are low-molar-mass esters soluble in water despite being unable to form hydrogen bonds with each other?

Esters lack hydrogen atoms bonded to oxygen (so they cannot hydrogen bond to each other), but their polar oxygen atoms can accept hydrogen bonds from water molecules.

What are the functions or practical applications of acetylcholine, methyl salicylate, and octyl ethanoate?

Acetylcholine acts as a neurotransmitter; methyl salicylate is a flavouring agent used in heating rubs; octyl ethanoate is used as an artificial orange flavouring.

How does controlled oxidation allow experimental differentiation among primary, secondary, and tertiary alcohols?

Controlled oxidation converts primary alcohols to aldehydes and secondary alcohols to ketones, while tertiary alcohols do not oxidize because the hydroxyl-bearing carbon lacks an attached hydrogen atom.