Ch. 12 - Alcohols, Ethers, Epoxides and ThiolsWorksheetSee all chapters
All Chapters
Ch. 1 - A Review of General Chemistry
Ch. 2 - Molecular Representations
Ch. 3 - Acids and Bases
Ch. 4 - Alkanes and Cycloalkanes
Ch. 5 - Chirality
Ch. 6 - Thermodynamics and Kinetics
Ch. 7 - Substitution Reactions
Ch. 8 - Elimination Reactions
Ch. 9 - Alkenes and Alkynes
Ch. 10 - Addition Reactions
Ch. 11 - Radical Reactions
Ch. 12 - Alcohols, Ethers, Epoxides and Thiols
Ch. 13 - Alcohols and Carbonyl Compounds
Ch. 14 - Synthetic Techniques
Ch. 15 - Analytical Techniques: IR, NMR, Mass Spect
Ch. 16 - Conjugated Systems
Ch. 17 - Aromaticity
Ch. 18 - Reactions of Aromatics: EAS and Beyond
Ch. 19 - Aldehydes and Ketones: Nucleophilic Addition
Ch. 20 - Carboxylic Acid Derivatives: NAS
Ch. 21 - Enolate Chemistry: Reactions at the Alpha-Carbon
Ch. 22 - Condensation Chemistry
Ch. 23 - Amines
Ch. 24 - Carbohydrates
Ch. 25 - Phenols
Ch. 26 - Amino Acids, Peptides, and Proteins
Johnny Betancourt

A hydroxyl group is an —OH group attached to another molecule. It can be found in alcohols, carboxylic acids, carbohydrates, and many more places. 

What does the word hydroxyl mean?

Hydroxyl is not to be confused with hydroxide! Let’s break apart the pieces. Hydrox indicates that there are oxygen and hydrogen atoms, and the suffix -yl indicates that it’s a substituent of another molecule or that it’s missing a hydrogen and has no charge. That means that the hydroxyl group is attached to a parent molecule. The suffix -ide indicates a negative charge. Hydroxide is an anion, not a substituent on a parent molecule!

Where can the hydroxyl group be found? 

The —OH group (hydroxyl group) appears in many types of molecules in chemistry, and the most common places to find it in O-Chem are alcohols, carboxylic acids, sulfonic acids, and carbohydrates. Let’s try to find them in these molecules: 

Unlabeled hydroxyl groupsUnlabeled hydroxyl groups

They were pretty easy to find, right? I’ve highlighted each hydroxyl group in each molecule below:

Labeled hydroxyl groupsLabeled hydroxyl groups

Properties:

Because oxygen is electronegative, many molecules with hydroxyl groups on them are actually soluble in polar solvents like water and are insoluble in nonpolar solvents like oils! But what about acidity? Hydroxyl groups, just like water, can function as either acids or bases. How it will act depends on a few factors including what functional group the hydroxyl group is part of as well as the concentration of protons in solution. 

These are by no means the only molecules on which you can find a hydroxyl group, but it should impart the right idea. Want to learn about how to identify functional groups, determine solubility, or predict boiling point? Check out my videos on those topics here!


Johnny Betancourt

Johnny got his start tutoring Organic in 2006 when he was a Teaching Assistant. He graduated in Chemistry from FIU and finished up his UF Doctor of Pharmacy last year. He now enjoys helping thousands of students crush mechanisms, while moonlighting as a clinical pharmacist on weekends.