Which of the following pairs correctly matches a carbon count to its given name?

• A. 5 carbon - petracarbon
• B. 6 carbon - decacarbon
• C. 7 carbon - monacarbon
• D. 10 carbon - hexacarbon

Answer: (A)

Understanding how the number of carbon atoms maps to its name helps you check these pairs quickly. In this set, the five-carbon option uses the name petracarbon, which is the one that matches the count correctly. The other pairs mix counts with names that would imply different numbers (for example, a seven-carbon count paired with a name that would suggest one carbon, or a ten-carbon count paired with a name that suggests six). So the five-carbon name petracarbon fits the required count, making it the correct pairing in this question.