Which of the following metals is extracted by electrolytic reduction?
A. Iron
B. Sodium
C. Copper
D. Zinc
Answer: Option B
Solution (By JKExamLibrary)
Highly reactive metals like sodium, potassium, calcium, and aluminum cannot be reduced by chemical reducing agents like carbon. They are extracted by the electrolysis of their molten chlorides or oxides. For example, sodium is extracted by the electrolysis of molten NaCl in the Down's cell.
Explanation:
Limestone (CaCO₃) decomposes to CaO, which is a basic flux. It reacts with the acidic impurity silica (SiO₂) to form calcium silicate (CaSiO₃), a fusible slag: CaO + SiO₂ → CaSiO₃. Slag floats on molten iron and is tapped separately. Reduction is done by CO/coke. Flux makes gangue removal easier. Slag is used in cement, road building.
Explanation:
The zeolite (permutit) process is used to remove water hardness. Zeolite (hydrated sodium aluminum silicate) exchanges its Na⁺ ions for the Ca²⁺ and Mg²⁺ ions in hard water, thus softening it. It does not remove bacteria, dissolved gases, or suspended solids.
Explanation:
Red litmus turning blue indicates that the solution is basic. Basic solutions have a pH greater than 7. Among the options, 10 is the only value greater than 7. pH 1 and 4 are acidic (turn blue litmus red), and 7 is neutral (no change in litmus color).
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