Which of the following is used as a chemical in fire extinguishers?
A. Magnesium sulfate
B. Sodium chloride
C. Calcium oxide
D. Sodium bicarbonate
Answer: Option D
Solution (By JKExamLibrary)
NaHCO₃ decomposes on heating, releasing CO₂ which smothers fire. Also used in soda-acid extinguishers with H₂SO₄ to produce CO₂. NaCl is table salt, CaO is quicklime, MgSO₄ is Epsom salt.
Explanation:
Single superphosphate (SSP) is manufactured by treating rock phosphate with sulfuric acid. The resulting product is a mixture of calcium dihydrogen phosphate (Ca(H2PO4)2), which is the actual fertilizer providing soluble phosphorus, and calcium sulfate (CaSO4, gypsum), which is an inactive filler.
Explanation:
Dmitri Mendeleev proposed the periodic law based on atomic mass. However, anomalies arose. In 1913, Henry Moseley discovered that the atomic number (number of protons) is the fundamental property. He proposed the modern periodic law: the properties of elements are periodic functions of their atomic numbers.
Explanation:
The critical temperature (Tc) is the temperature above which a gas cannot be liquefied, regardless of how much pressure is applied. Above Tc, the kinetic energy of the molecules is too high for intermolecular forces to hold them together in a liquid state, even under extreme pressure.
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