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Assertion : Thermoplastics become hard o...

Assertion : Thermoplastics become hard on heating and soft on cooling.
Reason : Themoplastics are cross - linked polymers which are soluble in many organic solvents.

A

If both assertion and reason are true and reason is the correct explanation of assertion .

B

If both assertion and reason are true but reason is not the correct explanation of assertion .

C

If assertion is true but reason is false.

D

If both assertion and reason are false.

Text Solution

Verified by Experts

The correct Answer is:
D
In themoplastics, the polymer chains are held together by weak intermolecular forces of attrction. The applied heat and pressure can easily overcome the weak forces of attraction which hold the chains and the polymer becomes soft and flexible. On cooling, they become hard and rigid.
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