A hydrocarbon has a molecular formula C₅H₁₂. The equation shows the reaction: C₅H₁₂ → C₃H₆ + C₂H₆. C₃H₆ undergoes addition polymerisation to form a macromolecule X.

1. aWhat type of reaction is shown by the equation? [1]
2. bName two structural isomers of C₅H₁₂ (draw them on paper). [2]
3. cName the macromolecule X. [1]
4. dDescribe the structure of the macromolecule (draw it on paper). [2]
5. eGive one problem caused by the commercial use of the macromolecule. Explain your answer. [2]

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