3 previous year UPSC Prelims questions on Chemistry: Inorganic Chemistry (Science and Technology). Choose an option to see the answer and explanation.
Explanations state facts as of the year each question was asked; words like “recently” refer to that year.
Showing 1–3 of 3 questions
Selenium is a semiconductor, meaning it has electrical conductivity that lies between that of metals and insulators. Its conductivity increases with exposure to light, making it useful in solar cells and photoelectric applications. Therefore, selenium is not a poor conductor of electricity.
Option (c) is correct: Zinc oxide (ZnO) is commonly referred to as philosopher’s wool. It is known as philosopher wool due to its wool-like texture. This name comes from the historical belief that zinc oxide could be produced by heating zinc metal in air, and it was once used by alchemists in their experiments. Zinc oxide is a white powder with applications in Cosmetics (UV-blocking in sunscreens), Rubber (activator in vulcanization), Paints (pigment, mildew-resistant) and Pharmaceuticals (antiseptic in ointments). Options (a), (b) and (d) are incorrect:
Zinc bromide (ZnBr₂) is used in dry cell batteries and photography. Zinc nitrate (Zn(NO₃)₂) is used in fertilizers and as a laboratory reagent. Zinc chloride (ZnCl₂) is used in chemical production and water treatment. None of these compounds are associated with the term "philosopher’s wool," which refers to zinc oxide (ZnO).
Option (b) is correct: German silver does not contain any silver at all. Alloy of copper (60%), nickel (20%), and zinc (20%). No actual silver content. Known for hardness, corrosion resistance, and silver-like appearance. Commonly used in jewelry, musical instruments, and coins. Options (a), (c) and (d) are incorrect:
Horn silver (also known as silver chloride, AgCl), gray, heavy halide mineral. Found in oxidized zones of silver-bearing veins. It is associated with silver and silver related minerals. Ruby silver: Collective term for pyrargyrite and proustite, both silver-bearing minerals with striking red colors. While Pyrargyrite(deep red color) is silver antimony sulfide (Ag₃ SbS₃) and Proustite (Scarlet red color) is Silver arsenic sulfide (Ag₃ AsS₃). Both crystallize in the trigonal system and possess a Mohr’s hardness of 2.5 and specific gravity of 5.82.. Lunar caustic: Another name for silver nitrate (AgNO₃). An inorganic compound containing silver. Has antiseptic properties. Used in various medical applications, including the treatment of warts and as a cauterizing agent.
| Q | UPSC year | Correct answer |
|---|---|---|
| 1 | 2007 | (b) Selenium |
| 2 | 2007 | (c) Zinc oxide |
| 3 | 2007 | (b) German silver |
This page covers 3 previous year UPSC Prelims GS Paper-I questions on Chemistry: Inorganic Chemistry (Science and Technology), asked from 1996 to 2008. Each has the correct answer and an explanation.
Attempt each question first, then open the answer and read the explanation for every option. Repeat by chapter, and track which statements UPSC reuses across years. Previous year questions show the exam pattern and difficulty level.
Questions on Chemistry: Inorganic Chemistry (Science and Technology) are available for 11 years, from 1996 to 2008. Use the Year filter to practise a single paper.
