Chemistry Industrial Chemistry PMDC Conceptual Practice
PMDC Verified Question 23 of 41
What fundamental structural feature is required for a small organic molecule to undergo addition (chain-growth) polymerization?
A
The presence of two terminal carboxylic acid or hydroxyl functional groups
B
The presence of one or more reactive carbon-carbon double or triple bonds
C
The capacity to eliminate small condensation byproducts such as water
D
A completely saturated, highly branched aliphatic hydrocarbon skeleton
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: The presence of one or more reactive carbon-carbon double or triple bonds
Concept:

Addition polymerization requires monomer unsaturation (\(\text{C}=\text{C}\) or \(\text{C}\equiv\text{C}\)) whose \(\pi\)-bonds open to link adjacent units into a continuous carbon chain.

Formula / Reaction:

$$n\,\text{CH}_2=\text{CHR} \longrightarrow -[\text{CH}_2-\text{CHR}]_n-$$

Solution:

  • The reactive \(\pi\)-bond undergoes addition via free-radical, cationic, or anionic intermediates without removing any atoms from the monomer.


Why other options are incorrect:

  • Option A: Terminal difunctional polar groups participate in condensation polymerization, not addition.


  • Option C: Byproduct elimination is the defining feature of condensation (step-growth) polymerization.


  • Option D: Saturated hydrocarbons (alkanes) lack reactive \(\pi\)-electrons and do not polymerize.

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