BPSC CCE Prelims
Everyday Chemistry Previous Year Questions (PYQs)
Practice solved questions for Everyday Chemistry with detailed step-by-step solutions, key insights, and trend analysis for BPSC CCE PRELIMS.
Solved Previous Year Questions
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Which Compound is known as night glowing pigment from below?
Detailed Explanation:
Europium-doped strontium aluminate (SrAl₂O₄:Eu²⁺,Dy³⁺) is the most efficient modern phosphorescent material used in night glowing pigments.
It absorbs light energy and slowly releases it in darkness, providing a bright afterglow lasting up to 12 hours. Other compounds listed (copper sulphide-doped zinc oxide, barium sulphate-doped copper carbonate, boron oxide-doped copper sulphate) do not exhibit significant or efficient phosphorescence for glow-in-the-dark applications.
Why oil is not stored in galvanized iron pot?
Detailed Explanation:
Galvanized iron is coated with zinc, which reacts with oil components to form toxic zinc compounds that make the oil unsafe for consumption.
The chemical reaction also causes rancidity, degrading the oil's taste, smell, and nutritional quality.
Moisture and acidic impurities in oil corrode the zinc coating, exposing the underlying iron to rust formation.
Since all three effects—toxicity, quality degradation, and corrosion—occur simultaneously, the correct answer is All of above.
Which compound is used for increase of octane rating?
Detailed Explanation:
Tetraethyllead (TEL) was historically the most widely used anti-knock agent added to gasoline to increase octane rating and prevent engine knocking.
Though highly effective, TEL is toxic and has been phased out globally; modern fuels use unleaded alternatives like ethanol and aromatic hydrocarbons.
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Catalyst used in hydrogenation of vegetable oil into vanaspati ghee is
Detailed Explanation:
Nickel (Ni) is the industrial catalyst used in the hydrogenation of vegetable oils to produce vanaspati ghee.
The process converts unsaturated fats (liquid oils) into saturated fats (solid ghee) by adding hydrogen in the presence of finely divided nickel at 140–225°C.
Which of the following are the constituents of a soda acid fire extinguisher?
Detailed Explanation:
Soda acid fire extinguisher contains dilute sulphuric acid (H₂SO₄) and sodium bicarbonate (NaHCO₃) solution in separate compartments.
When activated, the acid reacts with sodium bicarbonate: 2NaHCO₃ + H₂SO₄ → Na₂SO₄ + 2H₂O + 2CO₂, producing carbon dioxide gas that smothers the fire by cutting off oxygen supply.
Option 3 is correct.
Which one of the following is an example of melamine used for making floor tiles?
Detailed Explanation:
Melamine is a thermo-setting plastic that undergoes irreversible hardening when heated, forming a rigid three-dimensional network.
Used in floor tiles, kitchenware, and laminates, melamine-formaldehyde resin is heat-resistant, scratch-proof, and does not soften upon reheating. Polyethene, thermoplastics, and PVC are thermoplastics that soften when heated and can be remolded.
Which of the following is the main ingredient of cement?
Detailed Explanation:
Cement is manufactured using multiple key ingredients, making Option 5 the correct choice. The primary component is limestone (~60–65%), which provides calcium oxide. Silica clay (~20–25%) supplies silica, alumina, and iron oxide. Gypsum (~3–5%) is added post-burning to regulate setting time.
Since limestone, silica clay, and gypsum are all essential ingredients—not just one—the answer cannot be a single option.
Therefore, more than one ingredient is correct, making Option 5 the correct answer.
Select the incorrect statement out of the following
Detailed Explanation:
Acrylic is a synthetic polymer derived from petrochemicals (acrylonitrile), not cotton, and is known for its wool-like properties, not silk-like shine.
Rayon (viscose) is the fiber actually called artificial silk because it is derived from natural cellulose (wood pulp/cotton linters) and has a silk-like sheen and drape.
Option 1 is correct (cotton absorbs moisture for summer comfort), Option 2 is correct (polycarbonate is used in CDs for its transparency and durability), and Option 4 is correct (Teflon/PTFE provides non-stick coating).
Therefore, Statement 3 is incorrect as acrylic is not prepared from cotton nor called artificial silk, making Option 3 the correct answer.
Which of the following statements about graphite and diamond is true?
Detailed Explanation:
Graphite and diamond are allotropes of carbon—different physical forms of the same element. Both consist of pure carbon atoms and thus undergo identical chemical reactions (e.g., combustion in oxygen to form CO₂).
They differ drastically in crystal structure (graphite: hexagonal layers; diamond: tetrahedral lattice), hardness (graphite: soft; diamond: hardest natural material), and electrical conductivity (graphite: conducts; diamond: insulator)—eliminating Options 1, 2, and 3.
Therefore, only their chemical reactivity is identical, making Option 4 the correct answer.
Which of the following is the major constituent of the liquefied petroleum gas?
Detailed Explanation:
Liquefied Petroleum Gas (LPG) is primarily composed of propane (C₃H₈) and butane (C₄H₁₀), with butane being the major constituent in most commercial LPG blends used for cooking and heating.
Methane is the main component of natural gas (CNG), not LPG, while ethane is present only in trace amounts in petroleum gases.
Therefore, butane is the major constituent of LPG, making Option 4 the correct answer.
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