JEE Main levelSingle correct optionDifficulty 2 of 3pl131
Which description of novolac is correct?
AIt is a polyester of phenol and phthalic anhydride
BIt is a polymer of melamine and formaldehyde
CIt is a linear, fusible phenol-formaldehyde prepolymer made with excess phenol under acid catalysis, and it cross-links to bakelite on further heating with a formaldehyde source such as hexamethylenetetramine
DIt is a three-dimensional infusible network already when first formed
Answer: C
Novolac forms when phenol is in excess with an acid catalyst; the chains are linked by methylene bridges and are not cross-linked. Added formaldehyde (from hexamethylenetetramine) cross-links it into bakelite.