Bakelite classification (repair applied): which statement correctly identifies Bakelite?

Difficulty: Easy

Correct Answer: A thermosetting phenol–formaldehyde resin.

Explanation:


Introduction / Context:
The original options did not include a correct identification for Bakelite. Applying the Recovery-First Policy, we repair the MCQ by adding one accurate option that reflects standard materials knowledge.



Given Data / Assumptions:

  • Bakelite is produced from phenol and formaldehyde.
  • It cures to a crosslinked network (thermoset).
  • We ensure only one option is correct after repair.



Concept / Approach:
Bakelite is the archetypal phenol–formaldehyde thermoset. It is not an addition polymer (that would involve chain growth like styrene), not an elastomer (it is rigid), and not a thermoplastic (it does not remelt). Hence, the repaired correct description is a thermosetting phenolic resin.



Step-by-Step Solution:
Identify chemistry: phenol + formaldehyde → phenolic network.Classify as thermoset due to irreversible crosslinking.Select the repaired option (d) as correct.



Verification / Alternative check:
Historic and modern materials texts list Bakelite as the first widely commercialized thermoset plastic.



Why Other Options Are Wrong:
Addition polymer: wrong mechanism.Elastomer: mechanical behaviour does not match.Thermoplastic: does not soften/remelt upon heating.



Common Pitfalls:
Equating “moulded at heat” with thermoplasticity; thermosets also cure under heat and pressure.



Final Answer:
A thermosetting phenol–formaldehyde resin.

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