Polypropene is described as which of the following relative to polythene?

Polypropene is described as which of the following relative to polythene?

• A. Tough, durable, and stronger than polythene
• B. Brittle and weak, weaker than polythene
• C. Gas at room temperature
• D. Unreactive with water

Answer: (A)

The main idea being tested is how the structure of a polymer affects its mechanical properties. Polypropylene has extra methyl side groups along the backbone, which restrict how easily the chains can move and how closely they can pack together. This makes the material stiffer, more resistant to deformation, and generally tougher and stronger than polyethylene. Polyethylene, by contrast, has simpler chains with fewer bulky side groups, so the chains slide past each other more easily and it’s more flexible and less strong. So describing polypropylene as tough, durable, and stronger than polythene fits the structural result of those side groups and packing differences. The other options don’t capture this relative strength and toughness issue: both polymers are solids at room temperature (not gases), and while they are relatively unreactive with water, that doesn’t describe the comparative mechanical property in question.

The main idea being tested is how the structure of a polymer affects its mechanical properties. Polypropylene has extra methyl side groups along the backbone, which restrict how easily the chains can move and how closely they can pack together. This makes the material stiffer, more resistant to deformation, and generally tougher and stronger than polyethylene. Polyethylene, by contrast, has simpler chains with fewer bulky side groups, so the chains slide past each other more easily and it’s more flexible and less strong.

So describing polypropylene as tough, durable, and stronger than polythene fits the structural result of those side groups and packing differences. The other options don’t capture this relative strength and toughness issue: both polymers are solids at room temperature (not gases), and while they are relatively unreactive with water, that doesn’t describe the comparative mechanical property in question.