The process of heating an ore strongly in the absence of air is called:
A. Calcination
B. Roasting
C. Leaching
D. Smelting
Answer: Option A
Solution (By JKExamLibrary)
Calcination is the process of heating a concentrated ore strongly in the absence or limited supply of air. It is typically used for carbonate ores to drive off volatile impurities like CO₂ and H₂O (e.g., CaCO₃ → CaO + CO₂). Roasting is done in the presence of excess air.
Explanation:
Mass number (A) = protons (Z) + neutrons (N). So Z = A - N = 31 - 16 = 15. This is phosphorus (P). Atomic number 15, mass number 31. It has 15 protons and 15 electrons. Number of neutrons = 16. Isotope notation: ³¹₁₅P.
Explanation:
The Haber process synthesizes ammonia from nitrogen and hydrogen (N₂ + 3H₂ ⇌ 2NH₃). Finely divided iron acts as the catalyst, often with molybdenum as a promoter, to increase the rate of reaction at high pressure and moderate temperature. V₂O₅ is used in the Contact process.
Explanation:
NaOH is a strong base; it dissociates to give OH⁻ ions, making the solution basic (pH >7). Bases turn red litmus blue. Acids turn blue litmus red.
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