All organics contain which element?

• A. Carbon
• B. Hydrogen
• C. Oxygen
• D. Nitrogen

Answer: (A)

Organic compounds are defined by containing carbon as the backbone of their structure. Carbon’s ability to form four covalent bonds lets it bond to itself and to many other elements, creating a vast variety of stable, complex molecules. Because of this fundamental role, carbon is present in all organic substances, making it the universal element in organics.

Hydrogen is very common and often attached to carbon, but there are organics that have no hydrogen at all, such as carbon tetrachloride. Oxygen and nitrogen appear frequently in many organics, yet there are many hydrocarbons that contain only carbon and hydrogen. So while those elements are common, they aren’t universal.