Q. Al₂O₃ can be converted to anhydrous AlCl₃ by heating :
A) Al₂O₃ with HCl gas
B) Al₂O₃ with NaCl in solid state
C) a mixture of Al₂O₃ and carbon in dry Cl₂ gas
D) Al₂O₃ with Cl₂ gas
Explanation
[Solution from source] Heating Al₂O₃ with carbon in dry chlorine removes the oxygen as CO while chlorine combines with aluminium: Al₂O₃ + 3C + 3Cl₂ → 2AlCl₃ + 3CO. Without carbon, Cl₂ alone cannot displace oxygen from the very stable oxide, and HCl would give hydrated, not anhydrous, products. Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.