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JEE Main 2023 · Chemistry · d- and f-Block Elements and Metallurgy · medium

Consider the statements about metallurgy: (I) Cu in the Bessemer converter is formed by self-reduction: Cu2S+2Cu2O→6Cu+SO2. (II) In the blast furnace…

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Consider the statements about metallurgy: (I) Cu in the Bessemer converter is formed by self-reduction: Cu2S+2Cu2O→6Cu+SO2\mathrm{Cu_2S+2Cu_2O\to6Cu+SO_2}. (II) In the blast furnace for iron, limestone decomposes to CaO which combines with silica to form slag. (III) In the Hall-Heroult process, cryolite lowers the melting point of alumina and increases conductivity. (IV) In the Van Arkel process, ZrI4\mathrm{ZrI_4} is formed at about 1800 K1800\ \mathrm K over the crude metal and decomposed at about 870 K870\ \mathrm K. The number of correct statements is
  1. A. 3
  2. B. 4
  3. C. 2
  4. D. 1
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Answer: (A) 3

(I) True: matte's Cu2S\mathrm{Cu_2S} reacts with the Cu2O\mathrm{Cu_2O} formed on partial oxidation. (II) True: CaCO3→CaO+CO2\mathrm{CaCO_3\to CaO+CO_2}; CaO+SiO2→CaSiO3\mathrm{CaO+SiO_2\to CaSiO_3} (slag). (III) True. (IV) False: the temperatures are reversed. The iodide forms at the lower temperature (about 870870 K) and decomposes on the hotter tungsten filament (about 18001800 K). So 33 statements are correct.
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