The process of converting bauxite into pure alumina is called:
A. Hall-Héroult process
B. Bayer's process
C. Ostwald process
D. Contact process
Answer: Option B
Solution (By JKExamLibrary)
Bayer's process uses hot NaOH to dissolve alumina from bauxite, leaving behind insoluble impurities (red mud). Alumina is then precipitated. Hall-Héroult is electrolytic reduction of alumina to aluminium.
Explanation:
The standard reduction potential (E°) indicates the tendency of a species to gain electrons. A higher positive E° value means a greater tendency to be reduced, making it a stronger oxidizing agent. Fluorine (F2) has the highest standard reduction potential (+2.87 V), making it the strongest oxidizing agent among the choices.
Explanation:
Ethanol (C₂H₅OH) on heating with excess concentrated H₂SO₄ (dehydrating agent) at 170°C undergoes dehydration to give ethene (C₂H₄). This is an elimination reaction. Oxidation gives ethanoic acid; hydrogenation adds H₂; fermentation produces ethanol.
Explanation:
Aluminium oxide: Al³⁺ and O²⁻. To balance charges, 2 Al³⁺ (total +6) combine with 3 O²⁻ (total -6). Thus valency of Al is 3. It loses three electrons. Formula determined by criss-cross method.
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