1.

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

Answer»

If both assertion and reason are trueand reason is the CORRECT explanationof assertion .
If both assertion and reason are TRUE but reason is not the correct explanationof assertion .
If assertion is true but reason is false.
If both assertion and reason are false.

SOLUTION :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.


Discussion

No Comment Found

Related InterviewSolutions