MolSynapsequestion bank
MolSynapse / Question bank / Polymers / Condensation polymers: nylon, polyester, bakelite
JEE Advanced levelSingle correct optionDifficulty 3 of 3pl156

Assertion (A): Novolac, made from phenol and formaldehyde, is a fusible, soluble material that hardens on heating after addition of hexamethylenetetramine. Reason (R): Novolac is prepared with an excess of formaldehyde under basic conditions and already contains many hydroxymethyl groups.

  1. ABoth A and R are true and R is the correct explanation of A
  2. BBoth A and R are true but R is not the correct explanation of A
  3. CA is true but R is false
  4. DA is false but R is true

Answer: C

A is true: novolac is a linear, lightly branched prepolymer that cross-links to bakelite when a formaldehyde source is added. R is false: novolac is prepared with excess phenol and an acid catalyst, so chains are joined by methylene bridges and few hydroxymethyl groups remain. (Excess formaldehyde with base gives resole.)
Practice Polymers More on Condensation polymers: nylon, polyester, bakelite
Previous questionNext question

More questions on Condensation polymers: nylon, polyester, bakelite