The Chemical Industries chapter explores the role and significance of Pakistan’s major chemical-based industries in supporting economic development and daily life. It covers the production processes, raw materials, and uses of important industrial products such as fertilizers, cement, glass, caustic soda, and sulfuric acid. Students will also learn about the steps in manufacturing, the underlying chemical reactions, and the environmental and safety considerations associated with these industries.
1. Which raw material is used in the manufacture of urea fertilizer?
- A. Calcium carbonate and nitrogen
- B. Ammonia and carbon dioxide ✅
- C. Sulfur and nitrogen
- D. Sodium chloride and ammonia
Explanation: Urea is produced by reacting ammonia (NH3) with carbon dioxide (CO2).
2. The chemical formula of urea is:
- A. NH3
- B. CO(NH3)2
- C. CO(NH2)2 ✅
- D. NH4NO3
Explanation: The correct formula for urea is CO(NH2)2.
3. Which process is used to manufacture ammonia for fertilizers?
- A. Contact process
- B. Haber process ✅
- C. Solvay process
- D. Ostwald process
Explanation: The Haber process synthesizes ammonia from nitrogen and hydrogen under high pressure and temperature with an iron catalyst.
4. In cement manufacture, the main raw materials are:
- A. Clay and silica
- B. Limestone and gypsum
- C. Limestone, clay, and gypsum ✅
- D. Sand and soda ash
Explanation: Cement is made from limestone (CaCO3), clay (Al2O3), and gypsum (CaSO4·2H2O).
5. Which major compound is obtained during the calcination of limestone in cement production?
- A. Calcium sulfate
- B. Quicklime (CaO) ✅
- C. Slaked lime
- D. Calcium bicarbonate
Explanation: Heating limestone releases CO2 and produces quicklime (CaO).
6. Which raw material is NOT required for the glass industry?
- A. Sand (SiO2)
- B. Soda ash (Na2CO3)
- C. Limestone (CaCO3)
- D. Gypsum ✅
Explanation: Glass is made from silica, soda ash, and limestone; gypsum is not used.
7. The main constituent of soda-lime glass is:
- A. Potassium carbonate
- B. Sodium calcium silicate ✅
- C. Sodium bicarbonate
- D. Calcium sulfate
Explanation: Soda-lime glass is mainly sodium calcium silicate, made from silica, soda ash, and limestone.
8. Which process is used for the manufacture of caustic soda?
- A. Contact process
- B. Electrolysis of brine ✅
- C. Haber process
- D. Solvay process
Explanation: Caustic soda (NaOH) is produced by electrolyzing concentrated sodium chloride solution (brine).
9. The main by-product obtained during caustic soda production is:
- A. H2O
- B. Chlorine gas ✅
- C. CO2
- D. Nitrogen gas
Explanation: Electrolysis of brine yields chlorine gas at the anode, hydrogen gas at the cathode, and NaOH in solution.
10. Which process is used to manufacture sulfuric acid?
- A. Solvay process
- B. Haber process
- C. Contact process ✅
- D. Ostwald process
Explanation: The Contact process produces H2SO4 by oxidizing SO2 to SO3 and reacting it with water.
11. Which catalyst is used in the Contact process?
- A. Fe
- B. V2O5 ✅
- C. Pt
- D. Ni
Explanation: Vanadium(V) oxide is the catalyst for SO2 oxidation in the Contact process.
12. Which fertilizer is produced by the Ostwald process indirectly?
- A. Urea
- B. Ammonium nitrate ✅
- C. Potash
- D. Superphosphate
Explanation: The Ostwald process makes nitric acid from ammonia, which is then used to produce ammonium nitrate.
13. Which environmental problem is most associated with the cement industry?
- A. Oil spills
- B. Air pollution due to dust and CO2 emissions ✅
- C. Water acidification
- D. Thermal pollution
Explanation: Cement plants emit dust and large amounts of CO2 during limestone calcination.
14. Which is NOT a product of the fertilizer industry?
- A. Ammonium sulfate
- B. Urea
- C. Caustic soda ✅
- D. Ammonium nitrate
Explanation: Caustic soda is produced in the chemical industry but not as a fertilizer.
15. Which safety measure is essential in sulfuric acid plants?
- A. Dust masks only
- B. Corrosion-resistant equipment and acid-proof flooring ✅
- C. Using pure oxygen
- D. Avoiding catalysts
Explanation: Sulfuric acid is highly corrosive, so plant equipment must be resistant and workers must be protected.