Which option shows the displayed formula for ethane?

• A. CH3-CH3
• B. CH4
• C. C2H6
• D. CH3-CH2

Answer: (A)

Ethane has two carbon atoms joined by a single bond, with three hydrogens on each carbon. A displayed formula shows every atom and every bond, so the correct representation is two carbons connected by a single bond with three hydrogens on each carbon: CH3-CH3. This gives six hydrogens in total, matching ethane’s formula.

The other options don’t match the structure: CH4 is methane (one carbon, four hydrogens); C2H6 is the molecular formula for ethane but not the displayed structural diagram; CH3-CH2 would imply five hydrogens in total and is not ethane.