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1. What is used to cause artificial rain? = Silver iodide. 2. Which gas mixture do divers use for breathing? = Oxygen and helium or oxygen and nitrogen. 3. Which substance is found naturally in three states (solid, liquid and gas)? = Water. 4. Which alloy is used to make heating elements for electro thermal devices? = Nichrome. 5. Which method separates the components of a mixture? = Evaporation (for salt and water), filtration (for sand and water), distillation (for liquids), centrifugation (for cream from milk), and sublimation. 6. How many protons and neutrons are there in the nucleus of helium? = There are 2 protons and 2 neutrons. 7. What is the gas obtained when ethylene reacts with sulfur monochloride? = Mustard gas (Bis (2-chloroethyl) sulfide). 8. The presence of which substance causes the red colour of ruby? = Chromium oxide. 9. Which substance is used as both oxidizing agent and reducing agent? = Hydrogen peroxide (\(H_{2}O_{2}\)), Sulphur dioxide (\(SO_{2}\)) and nitrous acid (\(HNO_{2}\)). 10. Water is a good solvent, what is the reason for this? = Dielectric constant of water. 11. What is used to extinguish a petrol fire? = Foam type or dry powder fire extinguishers and carbon dioxide (CO₂). 12. Radioactivity is measured by? = Instruments such as the Geiger-Muller Counter (GM Counter) or scintillation counter. 13. Rutherford’s scattering experiment proved the presence of what in atoms? = proved the presence of a positively charged nucleus. 14. Which metals are added to convert iron into steel? = Carbon, manganese, chromium, nickel and vanadium. 15. With which element does carbon form the most compounds? = Hydrogen. 16. Which metal is found in pure form in the Earth’s crust? = Aluminum. 17. Which method is used for the extraction of silver? = Macarthur-Forest cyanide process. 18. What are the parts of a molecule? = Made up of two or more atoms that are chemically bonded to each other. 19. What is present in lime water? = Calcium hydroxide [Ca (OH)₂]. 20. Silver is mainly extracted from which ore? = Argentite or acanzite (Ag₂S). 21. What is commonly used to make transistors? = Semiconductor materials like silicon and germanium are used. 22. With which halogen element fluorine does it form maximum number of compounds? = Fluorine. 23. What are the components of the nucleus of an atom? = Protons and neutrons. 24. Who discovered radioactivity? = French scientist Henri Becquerel. 25. Which of the gases is present under pressure in cold drinks? = Carbon dioxide (CO₂). 26. Which element is present in the largest quantity in the universe? = Hydrogen. 27. The atomic number is based on which table? = Modern Periodic Table. 28. Which substance stops bleeding when applied to a cut? = Ferric chloride. 29. Lead is mainly extracted from which ore? = Galena. 30. In what form was plutonium first produced? = As neptunium-238. ========== ========= =========== रसायन विज्ञान से संबंधित -245.
1. कृत्रिम वर्षा कराने के लिए किसका प्रयोग किया जाता है? = सिल्वर आयोडाइड.
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