Question

Which alkane would have only the primary and tertiary carbon?

• A. Pentane
• B. 2-Methylbutane
• C. 2,2-Dimethylpropane
• D. 3,3-Dimethylbutane

Hint:

Primary carbons are attached to only one other carbon, while tertiary carbons are attached to three other carbons. Look for structures that fit these criteria.

Answer 1

The Correct Option is D

• 3,3-Dimethylbutane: Characterized by a tertiary carbon at position C3 and primary carbons at chain ends and branches. Primary carbons bond to one other carbon, while the tertiary carbon bonds to three others. Consequently, this molecule features both primary and tertiary carbons.
• Alternative molecules:
  • Pentane: Features secondary carbons exclusively, with the exception of the two terminal carbons, which are primary. Tertiary carbons are absent.
  • 2-Methylbutane: Contains secondary and primary carbons; tertiary carbons are not present.
  • 2,2-Dimethylpropane: Composed solely of tertiary carbons, lacking any primary carbons.

The alkane exhibiting both primary and tertiary carbons is thus identified as 3,3-Dimethylbutane.