How do functional groups influence the properties of organic compounds?

Functional groups determine the chemical behaviour and physical properties of organic compounds.

Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. They are like the special set of actors in a play who determine the plot of the story. The same functional group will undergo the same or similar chemical reactions regardless of the size of the molecule it is a part of. This is because the atoms of functional groups are linked to each other in a specific way, creating a predictable pattern of behaviour.

For instance, alcohols have a hydroxyl (-OH) functional group. This group is polar, meaning it has a slight negative charge on the oxygen and a slight positive charge on the hydrogen. This polarity allows alcohols to form hydrogen bonds with water molecules, making them soluble in water. The hydroxyl group also makes alcohols reactive, as it can participate in various chemical reactions, such as dehydration or oxidation.

Another example is the carboxyl (-COOH) functional group found in carboxylic acids. This group is acidic because it can donate a proton (H+) to a solution. The presence of this group gives carboxylic acids their acidic properties, such as a sour taste and the ability to neutralise bases.

In addition to influencing chemical behaviour, functional groups also affect physical properties such as boiling and melting points. For example, compounds with larger functional groups often have higher boiling points because more energy is needed to overcome the stronger intermolecular forces.

In summary, functional groups play a crucial role in determining the properties and reactions of organic compounds. By understanding these groups, we can predict how a particular compound will behave in different situations, which is a fundamental aspect of chemistry.