Which is the structural formula for propane?

Which is the structural formula for propane?

• A. CH4
• B. CH3 CH3
• C. CH3 CH2 CH3
• D. CH3 CH2 CH2 CH3

Answer: (C)

Propane is an alkane with three carbon atoms in a row and eight hydrogens. Its structural (condensed) formula shows three carbons linked together, with the end carbons bearing three hydrogens and the middle carbon bearing two hydrogens: CH3-CH2-CH3. This pattern matches C3H8, which is propane. The other options don’t fit: CH4 is methane (one carbon); CH3-CH3 would be ethane (two carbons); CH3-CH2-CH2-CH3 has four carbons, which is butane. So CH3-CH2-CH3 is the correct representation.

Propane is an alkane with three carbon atoms in a row and eight hydrogens. Its structural (condensed) formula shows three carbons linked together, with the end carbons bearing three hydrogens and the middle carbon bearing two hydrogens: CH3-CH2-CH3. This pattern matches C3H8, which is propane.

The other options don’t fit: CH4 is methane (one carbon); CH3-CH3 would be ethane (two carbons); CH3-CH2-CH2-CH3 has four carbons, which is butane. So CH3-CH2-CH3 is the correct representation.