1. The polyesters are obtained by polymerising the molecules of phthalic acid and ethene glycol.

    The polyesters are obtained by polymerising the molecules of phthalic acid and ethene glycol.

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  2. They are strong, elastic, light, wrinkle resistance, and easy to wash.

    They are strong, elastic, light, wrinkle resistance, and easy to wash.

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  3. Oxygen is more active than nitrogen because oxygen can combine with iron or zinc at ordinary temperature. But these metal do not combine with nitrogen even after strong heating.

    Oxygen is more active than nitrogen because oxygen can combine with iron or zinc at ordinary temperature. But these metal do not combine with nitrogen even after strong heating.

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