Which of the following best describes the primary focus of organic chemistry?

• A. The study of minerals and inorganic salts
• B. The study of the physical properties of metals
• C. The study of nuclear reactions and radioactive decay
• D. The study of compounds primarily composed of $C$ and $H$ atoms

Answer: (D)

Verified step by step guidance

1. Identify the main subject of organic chemistry, which is the study of compounds primarily composed of carbon (C) and hydrogen (H) atoms.
2. Recognize that organic chemistry focuses on the structure, properties, reactions, and synthesis of carbon-containing compounds.
3. Understand that other options such as the study of minerals and inorganic salts, physical properties of metals, and nuclear reactions fall under different branches of chemistry (inorganic chemistry, physical chemistry, and nuclear chemistry respectively).
4. Recall that carbon's unique ability to form four covalent bonds allows for a vast diversity of organic molecules, which is central to organic chemistry.
5. Conclude that the best description of organic chemistry is the study of compounds primarily composed of carbon and hydrogen atoms.