Functional groups determine the properties of organic molecules from "summary" of Organic Chemistry by John E. McMurry
Functional groups play a crucial role in determining the properties of organic molecules. Indeed, the functional group is the key structural feature that defines the behavior of a particular compound. Whether it is solubility, reactivity, acidity, or basicity, all these properties are heavily influenced by the presence of specific functional groups. For example, the presence of a hydroxyl group (-OH) in a molecule typically imparts properties such as increased solubility in water due to hydrogen bonding. This is in stark contrast to molecules with nonpolar functional groups like alkyl groups, which tend to be insoluble in water. Similarly, the presence of a carboxylic acid group (-COOH) confers acidity to a molecule, allowing it to donate a proton and react with bases. Furthermore, the reactivity of a molecule can also be attributed to its functional groups. For instance, molecules containing double or triple bonds exhibit different chemical behaviors compared to those with only single bonds. This is because the presence of pi bonds in these functional groups allows for the formation of multiple bonds with other atoms or molecules. In addition to solubility and reactivity, functional groups also influence the physical properties of organic molecules. For instance, the presence of aromatic rings imparts stability and rigidity to a molecule, leading to unique properties such as planarity and aromaticity. On the other hand, the presence of halogen atoms can significantly impact the boiling point and melting point of a molecule.- The diversity of properties exhibited by organic molecules can be attributed to the wide array of functional groups present in these compounds. By understanding the role of functional groups in determining the properties of organic molecules, chemists can predict and rationalize the behavior of various compounds in different chemical reactions and processes.
