Man-Made Materials — Set 1
Chemistry · मानव निर्मित सामग्री · Questions 1–10 of 50
Which synthetic polymer is commonly used for making non-stick coating on cooking utensils?
Correct Answer: A. Teflon
Teflon is used for non-stick surfaces because it has very low friction and is resistant to heat. It is chemically known as polytetrafluoroethylene (PTFE). This material is also highly resistant to chemical corrosion.
Which type of plastic cannot be remoulded upon heating once it has been set?
Correct Answer: D. Thermosetting plastics
Thermosetting plastics undergo a chemical change during molding that creates permanent cross-links between chains. Once they are set into a shape, they remain rigid even when subjected to high heat. Bakelite and melamine are prominent examples of this category.
What is the primary raw material used for the commercial production of Rayon?
Correct Answer: D. Cellulose
Rayon is produced from natural cellulose found in wood pulp or cotton linters. It is considered a semi-synthetic fiber because it is a regenerated natural material. This fiber is often called 'artificial silk' due to its shiny appearance.
Which of the following is the first fully synthetic fiber made by man?
Correct Answer: D. Nylon
Nylon was developed in the 1930s without using any natural raw materials like plant fibers. It is synthesized entirely from coal, water, and air. Its high strength and elasticity make it ideal for making parachutes and ropes.
Which plastic is widely used for manufacturing electrical switches and handles of pressure cookers?
Correct Answer: A. Bakelite
Bakelite is a poor conductor of electricity and heat, making it safe for electrical and kitchen use. It is a thermosetting polymer that does not soften at high temperatures. It was the first plastic made from synthetic components.
The monomer unit used to produce the polymer Polyvinyl Chloride (PVC) is?
Correct Answer: B. Vinyl chloride
Vinyl chloride molecules undergo polymerization to form the long-chain PVC polymer. This plastic is versatile and used for making pipes, raincoats, and flooring. It is one of the most widely produced synthetic plastic polymers.
Which material is known as 'artificial wool' because of its warmth and texture?
Correct Answer: D. Acrylic
Acrylic fibers are lightweight, soft, and warm, mimicking the properties of natural wool. They are used to make sweaters, blankets, and shawls at a lower cost than real wool. Acrylic is also resistant to moths and oils.
What substance is added to natural rubber during 'vulcanization' to improve its strength?
Correct Answer: B. Sulfur
Sulfur creates cross-links between rubber polymer chains during the heating process. This makes the rubber harder, more elastic, and less sticky than raw rubber. Charles Goodyear is credited with discovering this essential process.
Which polymer is used to manufacture bulletproof vests and high-performance sports gear?
Correct Answer: D. Kevlar
Kevlar is a heat-resistant and strong synthetic fiber with high tensile strength. Its molecular structure allows it to absorb and dissipate the energy of high-speed impacts. It is five times stronger than steel on an equal weight basis.
The variety of glass used in making laboratory equipment like beakers and flasks is?
Correct Answer: D. Pyrex glass
Pyrex, or borosilicate glass, has a very low coefficient of thermal expansion. This property prevents it from cracking when subjected to rapid temperature changes. It contains boron trioxide which enhances its chemical durability.