Which of the following statements is true regarding functional groups in organic molecules?

• A. Functional groups determine the chemical reactivity and properties of organic molecules.
• B. Functional groups are always composed of $C$ and $H$ atoms only.
• C. Functional groups are irrelevant to the solubility of organic compounds.
• D. Functional groups are only found in aromatic compounds.

Answer: (A)

Verified step by step guidance

1. Identify the definition of a functional group in organic chemistry. A functional group is a specific group of atoms within a molecule that is responsible for a characteristic chemical reaction of that molecule.
2. Understand that functional groups are not limited to carbon and hydrogen atoms. They often include other elements such as oxygen, nitrogen, sulfur, and halogens, which contribute to the molecule's reactivity.
3. Recognize that functional groups play a crucial role in determining the chemical reactivity and properties of organic molecules. They are the sites of chemical reactions and influence the physical properties of the compounds.
4. Consider the impact of functional groups on solubility. Functional groups can affect the solubility of organic compounds in water or other solvents due to their ability to form hydrogen bonds or ionic interactions.
5. Acknowledge that functional groups are not exclusive to aromatic compounds. They are present in a wide variety of organic molecules, including aliphatic compounds, and are essential for the diversity of organic chemistry.