Question

Identify total number carbon atoms present in undecane.

• A. 9
• B. 11
• C. 10
• D. 20

Hint:

Think of linguistic roots: "Deca" means 10, and "Un" means 1. Put them together: Un + deca = 1 + 10 = 11 carbon atoms!

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The problem requires us to determine the total number of carbon atoms contained in a single molecule of the alkane named undecane using standard IUPAC numerical prefixes.

Step 2: Detailed Explanation:
In organic chemistry, the names of saturated straight-chain hydrocarbons (alkanes) are determined by specific prefixes that denote the length of their carbon skeleton based on the general molecular formula $\text{C}_n\text{H}_{2n+2}$:

• Heptane ($n = 7$)

• Octane ($n = 8$)

• Nonane ($n = 9$)

• Decane ($n = 10$)

• Undecane ($n = 11$)

• Dodecane ($n = 12$)
The prefix "un-" (one) combined with "decane" (ten) stands for eleven. Therefore, an undecane molecule features a continuous straight chain containing exactly 11 carbon atoms, giving it the molecular formula $\text{C}_{11}\text{H}_{24}$.

Step 3: Final Answer:
The total number of carbon atoms present in undecane is 11, which corresponds to option (B).