Which of the following metals is obtained by the reduction of its oxide by aluminium?
A. Sodium
B. Zinc
C. Manganese
D. Iron
Answer: Option C
Solution (By JKExamLibrary)
Manganese is extracted by the aluminothermic process (Goldschmidt thermite process) where Mn₃O₄ is reduced by aluminium: 3Mn₃O₄ + 8Al → 9Mn + 4Al₂O₃. This works for metals with less reactivity than Al but not too reactive. Sodium is extracted by electrolysis. Iron is extracted by smelting with coke. Zinc by carbon reduction/electrolysis.
Explanation:
Cobalt-60 emits gamma rays used in radiotherapy to destroy cancerous cells. Carbon-12 and sodium-23 are stable. Phosphorus-32 is radioactive but used as tracer, not for cancer therapy.
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.
Explanation:
In a Daniel cell, the anode (where oxidation occurs) is a zinc rod immersed in ZnSO₄ solution. The cathode is a copper rod in CuSO₄ solution. Zinc is more reactive, so it loses electrons (Zn → Zn²⁺ + 2e⁻) and acts as the negative terminal of the cell.
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