Which prefix denotes four carbon atoms?

Which prefix denotes four carbon atoms?

• A. Eth
• B. Prop
• C. But
• D. Pent

Answer: (C)

In organic nomenclature, prefixes indicate how many carbon atoms are in the main carbon chain. Four carbons are shown with the prefix but-. It appears in names like butane, butene, and butanol, where the root changes with the functional group or bond type but the four-carbon prefix stays the same. Eth- is two carbons, prop- is three, and pent- is five, so four-carbon compounds use but-.

In organic nomenclature, prefixes indicate how many carbon atoms are in the main carbon chain. Four carbons are shown with the prefix but-. It appears in names like butane, butene, and butanol, where the root changes with the functional group or bond type but the four-carbon prefix stays the same. Eth- is two carbons, prop- is three, and pent- is five, so four-carbon compounds use but-.