1. Why some fibres are called Synthetic? Explain. (AS1)

Answer: Synthetic fibres are called so because they are not found naturally in plants or animals. Instead, they are artificially synthesized by human beings in industries using raw petrochemical materials derived from petroleum.

2. What are thermosetting plastics. Give two examples. (AS1)

Answer: Thermosetting plastics are synthetic polymers that once moulded into a specific shape cannot be softened or remelted by heating, because strong cross-links are established during their initial moulding process. Examples: Bakelite and Melamine.

3. Give reasons: "Why plastic containers are used as storing devices." (AS1)

Answer: Plastic containers are widely preferred for storage because plastics are non-reactive (they do not rust or corrode when in contact with moisture, air, or acids), lightweight, highly durable, strong, waterproof, and economical compared to metals.

1. How synthetic fibres have changed our daily life? (AS1)

Answer: Synthetic fibres have transformed our daily life by offering wrinkle-free, easily washable, highly durable, and affordable clothing options. They have also provided essential industrial materials like strong ropes, fishing nets, parachutes, and medical bandages that outperform natural fibres.

2. What would happen, if we make electric switches with thermoplastics? (AS2)

Answer: If electrical switches were made from thermoplastics, they would soften, melt, and deform easily due to the heat generated during electrical current flow or minor sparking, creating severe fire hazards and short-circuit risks.

3. What could be the consequences if plastics are not properly disposed? (AS7)

Answer: Improper disposal of plastic waste causes severe environmental hazards including choking of urban sewerage systems and drains, soil degradation, water pollution, accidental ingestion by stray cattle leading to fatal intestinal blockages, and toxic air pollution from open burning.

4. Rani wants to buy clothes for her parents for winter wear. What types of clothes would you suggest? Specify reasons. (AS7)

Answer: I would suggest winter garments made of Acrylic or blended wool (like terriwool). Acrylic is a synthetic artificial wool that provides excellent thermal insulation, is lightweight, durable, and significantly cheaper and more accessible than pure natural wool.

1. What made human beings search for alternatives to natural fibres? (AS2)

Answer: Rapid population growth, scarcity and high cost of natural fibres like silk and wool, complicated agricultural harvesting processes, and the industrial demand for stronger, waterproof, elastic, and weather-resistant materials prompted the invention of synthetic fibres.

2. Imagine what would happen if we do not discover plastics? (AS2)

Answer: Without the discovery of plastics, modern civilization would still depend heavily on wood, glass, leather, and heavy metals. This would result in massive deforestation, exorbitant manufacturing expenses, bulky household appliances, and severe constraints in electrical insulation, packaging, and medical technology.

3. Indiscriminate usage of plastic is a serious threat to biodiversity. What are the efforts of Government and Non-government organizations in this regard? (AS7)

Answer: Governments have implemented bans on ultra-thin polythene carry bags, mandated extended producer responsibility (EPR), and promoted municipal waste recycling programs. NGOs actively conduct environmental awareness rallies, distribute cloth bags, organize cleanup drives, and advocate for sustainable zero-waste policies.

1. Rayon is prepared by

a) Coal      b) Oxygen      c) Fibre      d) Cellulose

Answer: d) Cellulose

2. Necessity of labels on clothes

a) Required by law      b) To identify fabric content      c) Both A and B      d) They do not decompose

Answer: b) To identify fabric content

3. The material which is not decomposed by natural process is called

a) Non bio-degradable material      b) Bio-degradable material      c) Polyester      d) Nylon

Answer: a) Non bio-degradable material

4. The symbol representing recycling code 4 represents

a) PET      b) HDPE      c) LDPE      d) Others

Answer: c) LDPE

5. Which is a natural fibre among the following

a) Rayon      b) Nylon      c) Polyester      d) Silk

Answer: d) Silk

Experiment 1: Conduct a flame test to identify Thermoplastics and Thermosetting plastics.

Aim & Procedure: Take small pieces of plastic samples (comb, toothbrush handle, utensil handle, electric switch, melamine plate, mug) using tongs and bring them near a spirit lamp flame. Observe whether they soften and melt (thermoplastic) or char/burn with pungent smell without melting (thermosetting plastic).

Experiment 2: Flame test classification of threads (Wool, Silk, Cotton, Nylon, Sweater thread, Umbrella cloth, Rope).

Aim & Procedure: Unravel various threads and hold them to a flame using tweezers. Observe the burning behavior and smell: burning hair smell indicates wool/silk (natural protein); burning paper smell indicates cotton/rayon (cellulose); melting and shrinking in flame indicates synthetic fibres like nylon or polyester.

Project 1: Prepare a table of various synthetic fibres which are used to make household articles from them.

Guidelines & Table Structure: Create a structured chart listing synthetic fibres like Nylon, Polyester, Acrylic, and Rayon along with their everyday household and industrial applications such as ropes, toothbrushes, carpets, and bedsheets.

Project 2: Collect the figures made up of thermosetting, thermoplastics used in your daily life and make a poster.

Guidelines & Poster Structure: Cut out pictures or draw common plastic items found at home (combs, toothbrushes, electrical switchboards, melamine plates, buckets) and paste them on a chart paper, classifying them into thermoplastics and thermosetting plastics.

Project 3: Prepare a chart explaining recycling codes, full names, acronyms, and uses of plastics.

Guidelines & Chart Structure: Design a colorful chart displaying resin identification codes 1 to 7 with their full technical names (PET, HDPE, PVC, LDPE, PP, PS, Other), recycling status, and typical household products made from them.