Chemistry · General trends in properties of the first-row transition elements: physical properties, ionization enthalpy, oxidation states, atomic radii, colour, catalytic behaviour, magnetic properties, complex formation, interstitial compounds, alloy formation

The correct statement is :

The correct statement is :

  • A. leaching of bauxite using concentrated \( N a O H \) solution gives sodium aluminate and sodium silicate
  • B. The blistered appearance of copper during the metallurgical process is due to the evolution of \( C O_{2} \)
  • C. pig iron is obtained from cast iron
  • D. the Hall-Heroult process is used for the prodeuction of aluminium and iron.

Step-by-step solution

Option A correctly describes the leaching of bauxite with concentrated NaOH: Al2O3 forms sodium aluminate (NaAlO2) and the impurity SiO2 forms sodium silicate (Na2SiO3), both soluble. Option B is false because blister copper appearance is due to SO2 evolution, not CO2. Option C is false because pig iron is obtained directly from blast furnace and cast iron is made from pig iron. Option D is false because Hall-Heroult process is only for aluminium, not iron.
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