Assertion (A) Network polymers are thermosetting.
Reason (R) Network polymers have high molecular mass.
(a) Assertion and Reason both are correct statement But reason does not explain Assertion.
(b) Assertion and Reason both are correct statement and Reason explains the Assertion.
(c) Both assertion and reason are wrong statements.
(d) Assertion is correct statement and Reason is wrong statement.
(e) Assertion is wrong statement and reason is correct statement.
Answer: (a). Assertion and reason both are correct and reason does not explain assertion.
Network polymers are thermosetting because they can't be reused after heating once. Because after heating it undergoes extensive cross-linking in moulds and again become infusible.
Extensive cross-linking during polymerisation leads to the formation of a three-dimensional network which is hard, infusible and insoluble.