Question

Determine the correctness or otherwise of the following Assertion [a] and Reason [r].
[a]: In boiling water, polyester POY shows higher shrinkage than polyester FDY.
[r]: Molecular chain orientation is higher in polyester FDY than polyester POY.

• A. Both [a] and [r] are true and [r] is the correct reason for [a]
• B. Both [a] and [r] are true but [r] is not the correct reason for [a]
• C. Both [a] and [r] are false
• D. [a] is true but [r] is false

Hint:

- POY generally has more shrinkage than FDY due to lower molecular orientation. FDY is fully drawn and has higher orientation, leading to better dimensional stability.

Answer 1

The Correct Option is D

The assertion [a] is true. Polyester POY (Partially Oriented Yarn) typically shows higher shrinkage in boiling water compared to polyester FDY (Fully Drawn Yarn), as POY has less molecular orientation.
However, the reason [r] is false. In fact, polyester FDY has a higher level of molecular orientation than POY due to the higher drawing process involved in its production. This higher orientation leads to better dimensional stability, which results in lower shrinkage during boiling.
Thus, while [a] is correct, [r] is incorrect as the explanation for [a].
Final Answer: The correct answer is \( \boxed{D} \).