Chemistry 2nd Ch 05 Economical Chemistry

Chemistry 2nd Paper Chapter 5 : Economical Chemistry HSC (English Version) - Question Bank Creative Question A. Knowledge Base Questions 1. What is ETP? [J.B., S.B., Ch.B.16, D.B-19] Answer: ETP stands for E uent Treatment Plant. It is a facility designed to purify industrial wastewater for its reuse and to release safe water to the environment from the harmful eects of e uents. 2. What is called nano particle? [Ch.B., Co.B.16, Ch.B. B-19, B-19, D.B-19] Answer: Particles with at least one dimension between 1 and 100 nanometers (10−9 m) in size are called nanoparticles. They exhibit unique physical and chemical properties compared to bulk materials. 3. What is called ceramic? [Dn.B.16] Answer: Ceramics are non-metallic, inorganic solid materials made from compounds of metal and non-metal minerals (like clay/kaolinite) that are shaped and then hardened by heating to high temperatures. 4. What is called portland cement? Answer: Portland cement is the most common type of cement, produced by heating limestone and clay mixtures in a kiln to form clinker, which is then ground with a small amount of gypsum to a ne powder. 5. What is called leather tanning? [J.B.-19] Answer: Leather tan

Answer: Gypsum (CaSO4 · 2 H2O) is added (about 2-3%) during the grinding of cement clinker to act as a retarder. Without gypsum, the tricalcium aluminate in cement hydrates instantly, causing a  ash set (rapid hardening) which makes the cement unworkable. Gypsum slows down this setting time. 2. Why is the presence of sulfur in coal harmful? [J.B., S.B.16] Answer: When coal containing sulfur is burned, the sulfur oxidizes to sulfur dioxide (SO2). In the atmosphere, SO2 reacts with oxygen and water vapor to form sulfuric acid (H2SO4), leading to acid rain. Acid rain damages ecosystems, corrodes buildings, and harms human health. 3. Why is Portland cement called as hydraulic cement? [Dn.B.16] Answer: Portland cement is called a hydraulic cement because it sets and hardens due to a chemical reaction with water (hydration). The hydration products are insoluble in water, allowing the cement to retain its strength and stability even when continuously exposed to or submerged in water. 4. What is the Culet used in the manufacturing of glass? [D.B-19] Answer: Cullet refers to crushed, recycled waste glass that is added to the raw materials (sand, soda ash, limestone) in glass manufacturi

Industry Components No-1 Air, natural gas No-2 Leather, lime, Na2Cr2O7, H2SO4 No-3 Scrap ship c. Describe the production of iron from the components of Industry-3. d. Which one plays more role in environmental pollution between the Industry-1 and Industry-2? Analyze. Answer: (c) Industry-3 refers to the ship-breaking and steel recycling industry. The production of iron (or steel) from scrap ships involves: 1. **Cutting and Segregation:** The steel hull and parts of the scrap ship are cut into smaller pieces using gas torches and segregated based on quality. 2. **Melting:** The sorted scrap steel is fed into an Electric Arc Furnace (EAF) or an Induction Furnace. Electric currents are passed through graphite electrodes into the scrap, generating immense heat (up to 3000◦C) that melts the steel. 3. **Re ning and Casting:** Impurities (like sulfur and phosphorus) are removed by adding uxes (like limestone), forming a slag that oats on the molten metal. The puri ed molten steel is then poured into molds or continuous casting machines to form billets, which are rolled into steel rods or sheets for construction. (d) Industry-1 uses air and natural gas, likely to produce urea fertilizer (v