Unit I–III: Alcohols, Phenols, Ethers, Aldehydes, Ketones, and Carboxylic Acids — Theory Review

A set of flashcards covering key concepts related to alcohols, phenols, ethers, aldehydes, ketones, and carboxylic acids in organic chemistry.

What are alcohols?

Organic compounds containing one or more hydroxyl (–OH) groups attached to carbon atoms.

Name three applications of alcohols in medicine and industry.

Disinfectants, solvents, and fuels.

What is the carbinol atom?

The carbon atom that is bonded directly to the hydroxyl (–OH) group.

What is the general molecular formula for saturated alcohols?

CnH₂n+1OH.

How can alcohols be classified based on the location of the carbinol atom? Give an example.

Primary (attached to one carbon), Secondary (attached to two carbons), Tertiary (attached to three carbons).

How can alcohols be classified based on the number of OH groups? Provide examples.

Monohydric (1 OH), Dihydric (2 OHs), Trihydric (3 OHs).

What are three different physical properties of alcohols?

High boiling point, polar molecules, soluble in water at low molecular weight.

How does steric hindrance affect the reactivity of alcohols?

Primary alcohols are more reactive; tertiary are less reactive due to bulky groups blocking access to the –OH carbon.

What is the difference between denatured alcohol and absolute alcohol?

Denatured alcohol is ethanol mixed with impurities; absolute alcohol is 100% pure ethanol.

What are phenols?

Aromatic compounds with a hydroxyl (–OH) group directly attached to a benzene ring.

How do alcohols differ from phenols?

Alcohols have –OH on aliphatic carbons; phenols have –OH bonded to aromatic rings.

Which is more acidic, an alcohol or a phenol, and why?

Phenols are more acidic because the phenoxide ion is stabilized by resonance.

How do hydrogen bonds affect the solubility of alcohols?

They increase solubility in water for lower molecular weight alcohols.

What types of reactions are characteristic of alcohols?

Dehydration, oxidation, and substitution.

What types of reactions are characteristic of phenols?

They undergo substitution on the aromatic ring such as halogenation, nitration, and sulfonation.

How do electron-withdrawing groups affect the acidity of phenols?

They increase acidity by stabilizing the negative charge on oxygen through resonance or induction.

What are ethers?

Compounds with two alkyl or aryl groups bonded to the same oxygen atom (R–O–R′).

Name three physical properties of ethers.

Polar, colorless, and less dense than water with low boiling points.

Are ethers capable of forming hydrogen bonds with other ethers?

No, because they lack a hydrogen atom directly bonded to oxygen.

What are the applications of ethers?

Used as anesthetics, solvents, antiseptics, and refrigerants.

What is the difference between symmetric and asymmetric ethers? Give examples.

Symmetric: same alkyl groups (diethyl ether); Asymmetric: different alkyl groups (ethyl methyl ether).

What are epoxides or oxiranes?

Three-membered cyclic ethers with one oxygen atom forming a strained ring.

How does angular strain affect the reactivity of epoxides?

The 60° bond angles cause strain, making epoxides highly reactive and unstable.

What is the difference between aldehydes and ketones? Provide an example of each.

Aldehydes have the carbonyl group at the end of the chain (R–CHO), ketones have it between two carbons (R–CO–R′).

What type of three-dimensional conformation does the carbonyl group have?

Planar structure with sp² hybridization and 120° bond angles.

What is the difference between dipole–dipole interactions and hydrogen bonds?

Dipole–dipole are attractions between polar molecules; hydrogen bonds involve hydrogen bonded to highly electronegative atoms (O, N, F).

How does molecular weight affect the boiling point of aldehydes and ketones?

Boiling points increase with molecular weight but are lower than alcohols since they can’t hydrogen bond with each other.

What are the medical and industrial applications of aldehydes and ketones?

Used in making plastics, resins, disinfectants, perfumes, solvents, and pharmaceuticals.

Explain the difference between nucleophilic and electrophilic addition reactions.

Nucleophilic addition: electron-rich species attacks carbonyl carbon; Electrophilic addition: electron-poor species attacks electron-rich bonds.

What is the definition of carboxylic acids?

Organic acids containing both carbonyl (C=O) and hydroxyl (–OH) groups on the same carbon (–COOH).

Why do carboxylic acids behave as acids?

They can donate a proton (H) from their –OH group.

Why is the carboxylate ion so stable?

Because the negative charge is delocalized through resonance over two oxygen atoms.

Why do carboxylic acids have high boiling points?

Strong hydrogen bonding between molecules requires more energy to separate them.

Where is the alpha carbon located in a carboxylic acid?

It is the carbon atom adjacent to the carboxyl carbon.

How do electron-withdrawing and electron-donating groups affect the acidity of carboxylic acids?

Electron-withdrawing groups increase acidity; electron-donating groups decrease it.

What are the medical and industrial applications of carboxylic acids?

Used in making food additives, plastics, soaps, pharmaceuticals, and disinfectants.

What are fatty acids? Give an example.

Long-chain carboxylic acids (C₆–C₁₈) derived from fats and oils, e.g., palmitic acid.

What are omega-3 and omega-6 fatty acids?

Polyunsaturated fatty acids with double bonds near the methyl end of the carbon chain.

What are derivatives of carboxylic acids?

Acid chlorides, anhydrides, esters, and amides.

What are acid chlorides? Provide an example.

Carboxylic acid derivatives where –OH is replaced by –Cl, e.g., acetyl chloride (CH₃COCl).

What are acid anhydrides? Provide an example.

Compounds formed by removing water between two carboxylic acids, e.g., acetic anhydride.