How many constitutional isomers are possible for the molecular formula $C_6{H}_{14}$?

• A. $4$
• B. $5$
• C. $3$
• D. $6$

Answer: (B)

Verified step by step guidance

1. Understand that the molecular formula C\6H\14 corresponds to alkanes with six carbon atoms and only single bonds, meaning we are looking for all possible structural (constitutional) isomers of hexane.
2. Recall that constitutional isomers differ in the connectivity of atoms, so we need to consider all unique ways to arrange six carbon atoms in a chain or branched structures without changing the molecular formula.
3. Start by drawing the straight-chain alkane, which is n-hexane, as the first isomer.
4. Next, consider all possible branched isomers by moving methyl (–CH\3) groups to different positions on the main carbon chain, ensuring no duplicates and that each structure is unique in connectivity.
5. Count all unique structures obtained from these arrangements to find the total number of constitutional isomers for C\6H\14.