Questions
5–8 MCQs per paper
Difficulty
Medium
Importance
High yield for HPCL/NTPC/ONGC
Overview
Chemical Technology covers the industrial scale manufacturing processes for essential products like fertilizers, polymers, and refined petroleum. It is a high-yield area in PSU exams where memory-based recall of reaction conditions, catalysts, and process names translates directly into marks.
Petroleum Refining Processes
Petroleum refining involves the separation and conversion of crude oil into usable fuels and petrochemical feedstocks. Understanding the mechanisms of cracking and reforming is essential for identifying reaction conditions in industrial setups.
- Catalytic Cracking uses Zeolites (acid catalysts) to increase gasoline yield.
- Reforming (Platforming) involves Platinum on Alumina catalyst.
- Hydrocracking operates at high pressure to improve fuel quality.
- Coking is a thermal cracking process for heavy residues.
- Sweetening process uses lead sulfide/copper chloride to remove mercaptans.
Fertilizer & Ammonia Production
This section focuses on the Haber-Bosch process and related downstream nitrogenous fertilizer manufacturing. Questions frequently target the catalyst composition and reaction equilibrium shifts.
- Haber Process: N2 + 3H2 ⇌ 2NH3
- Catalyst: Promoted Iron (Fe) with K2O and Al2O3.
- Operating conditions: 400-500°C and 200-300 atm pressure.
- Urea synthesis: Ammonia + Carbon Dioxide → Ammonium Carbamate → Urea.
- Contact process for H2SO4 uses Vanadium Pentoxide (V2O5) catalyst.
Polymer Manufacturing
Industrial polymerization techniques dictate the physical properties of the final plastic products. You must memorize the initiators and process classifications for common synthetic polymers.
- LDPE: High pressure (1000-3000 atm) free-radical polymerization.
- HDPE: Low pressure using Ziegler-Natta catalysts (TiCl4 + Al(C2H5)3).
- Polyvinyl Chloride (PVC): Suspension or emulsion polymerization.
- Polystyrene: Addition polymerization using free-radical initiators.
- Step-growth polymerization leads to Nylon-6,6.
Chlor-Alkali Industry
The production of chlorine and caustic soda is a foundational industrial process. Exams test the efficiency and operational differences between common electrolytic cell designs.
- Diaphragm Cell: Uses asbestos diaphragm to separate cathode/anode.
- Mercury Cell: Uses liquid mercury cathode, produces high purity NaOH.
- Membrane Cell: Uses ion-exchange membrane (Nafion), most energy-efficient.
- Net reaction: 2NaCl + 2H2O → 2NaOH + Cl2 + H2.
- Current efficiency in membrane cells is typically >95%.
Formula Sheet
Haber Process: N2 + 3H2 ⇌ 2NH3
Urea Formation: 2NH3 + CO2 ⇌ NH2CONH2 + H2O
Chlor-Alkali: 2NaCl + 2H2O → 2NaOH + Cl2 + H2
Exam Tip
Memorize the 'Catalyst-Process-Pressure' matrix for major industrial reactions as these are the most common source of direct MCQs.
Common Mistakes
- Confusing the catalyst used for Ammonia synthesis (Iron) with that used for Sulfuric acid production (V2O5).
- Mixing up conditions for LDPE (high pressure) and HDPE (low pressure/catalytic).
- Failing to differentiate between Diaphragm and Membrane cell operational efficiencies.
More Revision Notes
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