Hydroxy

Definition

The hydroxy group, represented by the chemical formula -OH, is a functional group consisting of an oxygen atom bonded to a hydrogen atom. It is a key component in the classification and naming of organic compounds, particularly alcohols and phenols.

5 Must Know Facts For Your Next Test

1. The presence of a hydroxy group in a molecule is denoted by the prefix 'hydroxy-' in the IUPAC name of the compound.
2. Alcohols are classified based on the number of carbon atoms attached to the carbon bearing the hydroxy group: primary, secondary, or tertiary.
3. Phenols are a class of aromatic compounds with a hydroxy group directly attached to a benzene ring, which gives them distinct chemical properties.
4. The hydrogen atom in the hydroxy group can be involved in hydrogen bonding, which influences the physical and chemical properties of the compound.
5. The electronegativity of the oxygen atom in the hydroxy group makes it a polar functional group, contributing to the solubility and reactivity of the compound.

Review Questions

• Explain the role of the hydroxy group in the classification and naming of alcohols.
  • The hydroxy group (-OH) is the defining feature of alcohols, a class of organic compounds. The presence and location of the hydroxy group are used to classify alcohols as primary, secondary, or tertiary, based on the number of carbon atoms attached to the carbon bearing the hydroxy group. Additionally, the hydroxy group is used in the IUPAC naming system to indicate the presence of an alcohol, with the prefix 'hydroxy-' being used to denote the location of the hydroxy group within the molecule.
• Describe how the hydroxy group influences the properties of phenols compared to other aromatic compounds.
  • Phenols are a class of aromatic compounds where the hydroxy group (-OH) is directly attached to a benzene ring. The presence of the hydroxy group gives phenols distinct chemical properties compared to other aromatic compounds. The hydrogen atom in the hydroxy group can participate in hydrogen bonding, which affects the solubility and reactivity of phenols. Additionally, the electronegativity of the oxygen atom in the hydroxy group influences the acidity and reactivity of phenols, making them more acidic than alcohols and more reactive towards electrophilic aromatic substitution reactions.
• Analyze the role of the hydroxy group in determining the overall chemical reactivity and behavior of organic compounds.
  • The hydroxy group (-OH) is a highly polar functional group that significantly influences the chemical reactivity and behavior of organic compounds. The electronegativity of the oxygen atom makes the hydroxy group a good hydrogen-bond donor and acceptor, which affects the solubility, boiling points, and intermolecular interactions of the compounds. Additionally, the hydroxy group can participate in various chemical reactions, such as substitution, elimination, and oxidation, due to the reactivity of the hydrogen atom and the polarity of the O-H bond. The presence and position of the hydroxy group are crucial in determining the overall reactivity, physical properties, and classification of organic compounds, particularly alcohols and phenols.

Related terms

Alcohol: An organic compound containing a hydroxy group (-OH) attached to a saturated carbon atom.

Phenol: An aromatic organic compound with a hydroxy group (-OH) attached directly to a benzene ring.

Functional Group: A specific group of atoms within a molecule that determines the molecule's chemical properties and reactivity.