Which of the following salts is used in fire extinguishers?
A. Calcium sulfate
B. Potassium nitrate
C. Sodium bicarbonate
D. Sodium chloride
Answer: Option C
Solution (By JKExamLibrary)
Sodium bicarbonate (NaHCO₃) is used in soda-acid fire extinguishers. It reacts with sulfuric acid to produce CO₂, which smothers the fire. Also, dry powder extinguishers use NaHCO₃. It is also baking soda.
Explanation:
Amorphous solids like glass do not have a sharp melting point; they soften over a range of temperatures. Crystalline solids have sharp melting points and long-range order. Glass is an insulator.
Explanation:
Oxygen (atomic number 8) has electronic configuration 2,6. It needs 2 more electrons to complete its octet. In water (H₂O), it shares two electrons (one each with two hydrogen atoms), forming two covalent bonds. Hence valency = 2. Oxidation number is -2.
Explanation:
CNG stands for Compressed Natural Gas. It is primarily methane stored at high pressure. It is considered a cleaner fuel than petrol or diesel because it produces fewer pollutants like carbon monoxide and unburnt hydrocarbons, and it leaves no residue upon combustion.
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