Basic properties of plastics in building applications: Identify the incorrect statement among the following general properties of plastics.

Introduction / Context:
Plastics (thermoplastics and thermosets) are widely used because they resist many chemicals, are lightweight, and are good electrical insulators. However, their mechanical behavior differs from metals; specifically, their ductility in the metallurgical sense is limited.

Given Data / Assumptions:

• General property statements typical of civil/building materials exams.
• We look for the statement that is not generally true for plastics.

Concept / Approach:
Many plastics are resistant to water and numerous chemicals, exhibit long service life in benign environments, and are excellent electrical insulators due to high resistivity. “Ductility,” defined as the ability to undergo significant plastic deformation in tension before fracture (like mild steel), is typically not a defining property of most engineering plastics in structural contexts; many are relatively brittle at room or low temperatures or display limited elongation-to-failure compared with metals.

Step-by-Step Solution:

Verification / Alternative check:
Materials handbooks report high volume resistivity and corrosion resistance of plastics, but variable and often modest tensile ductility; some thermosets are distinctly brittle.

Why Other Options Are Wrong:

• Chemical resistant/durable/insulators: broadly correct, acknowledging environmental limits (UV, solvents, temperature).

Common Pitfalls:

• Overgeneralizing from one plastic to all; properties vary widely across families.
• Confusing impact toughness with tensile ductility.

Final Answer:
Plastics are ductile