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: This molecule has a tertiary carbon at the central position (C3) and primary carbons at the ends of the chain and the branches. The primary carbons are attached to only one other carbon, and the tertiary carbon is attached to three other carbon atoms. Thus, this molecule contains both primary and tertiary carbons.
• Other options:
  • Pentane: All carbons in pentane are secondary, except the two terminal carbons which are primary. It does not have a tertiary carbon.
  • 2-Methylbutane: This molecule has secondary and primary carbons, but no tertiary carbon.
  • 2,2-Dimethylpropane: This molecule contains only tertiary carbons but no primary carbons.

Therefore, the correct alkane that has both primary and tertiary carbons is 3,3-Dimethylbutane.