Final answer:
The main reaction in question involves the Hall-Heroult process, where aluminum oxide is electrolyzed in molten cryolite to produce aluminum and carbon dioxide gas. Chromium oxide does not react in this context but can be incorporated into aluminum oxide to create rubies for laser applications.
Step-by-step explanation:
The reaction between cryolite, aluminum oxide, and chromium oxide mainly pertains to the extraction of aluminum via an electrolytic process known as the Hall-Heroult process. In this process, aluminum oxide (Al₂O₃) is dissolved in molten cryolite (Na₃AlF₆) to lower the melting point of the aluminum oxide and decrease the energy required for electrolysis. The mixture is typically composed of approximately 5% aluminum oxide and 95% cryolite.
During electrolysis at approximately 1000°C, aluminum is produced at the cathode and carbon dioxide gas is released at the carbon anode. The overall reaction is: 2 Al₂O₃ (l) + 3 C(s) → 4 Al(l) + 3 CO₂ (g). As for chromium oxide (Cr₂O₃), when combined with aluminum oxide, it doesn't take part in the primary reaction for aluminum extraction, but rather is used in creating materials like rubies where chromium atoms provide the red color and allow for the construction of devices such as ruby lasers.