How long are the carbon chains in the manufacture of polyethylene?

• A. 4,000-40,000
• B. 400-4,000
• C. 40-400
• D. 4-40

Answer: (A)

Polymer molecules are built by linking many repeating units, and in polyethylene each repeating unit adds two carbon atoms. When many of these units join, the chains become very long—thousands of carbon atoms in a single molecule. That’s why polyethylene is described as having long carbon chains: typically in the range of thousands to tens of thousands of carbon atoms per chain. The option 4,000–40,000 reflects this, whereas the smaller ranges (hundreds or tens) would describe much shorter molecules, not the long polymer chains used in polyethylene.