JEE Main levelSingle correct optionDifficulty 2 of 3pl065
Assertion (A): Bakelite, once set, cannot be softened and remoulded by heating. Reason (R): Bakelite has a three-dimensional network of methylene bridges between phenol rings.
ABoth A and R are true but R is not the correct explanation of A.
BBoth A and R are true and R is the correct explanation of A.
CA is true but R is false.
DA is false but R is true.
Answer: B
Heating bakelite cannot make its chains flow because every chain is covalently tied to others through −CHX2− bridges. This cross-linked structure is the reason it is thermosetting.