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In the electrolysis of alumina, cryolite...

In the electrolysis of alumina, cryolite is added to

A

Lower the melting point of alumina

B

Increase the electrical conductivity

C

Minimise the anode effect

D

Remove the impurities from alumina

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The correct Answer is:
**Step-by-Step Solution:** 1. **Understanding the Problem**: The question asks why cryolite is added during the electrolysis of alumina (Al₂O₃). 2. **Properties of Alumina**: Pure alumina has two main issues: - It is a poor conductor of electricity. - It has a very high melting point of approximately 2000 °C. 3. **Challenges in Electrolysis**: Due to the high melting point, if electrolysis were to be performed on pure alumina, it would require extremely high temperatures, which could lead to the vaporization of the aluminum metal produced. 4. **Role of Cryolite**: Cryolite (Na₃AlF₆) is added to the electrolysis process for the following reasons: - **Increases Electrical Conductivity**: Cryolite enhances the conductivity of the alumina mixture, allowing for a more efficient electrolysis process. - **Lowers Melting Point**: The addition of cryolite significantly reduces the melting point of the alumina mixture, making it easier to maintain a molten state during electrolysis. 5. **Conclusion**: Therefore, the addition of cryolite in the electrolysis of alumina serves to both lower the melting point of alumina and increase its electrical conductivity, facilitating the electrolysis process. **Final Answer**: Cryolite is added to lower the melting point of alumina and increase its electrical conductivity. ---
**Step-by-Step Solution:** 1. **Understanding the Problem**: The question asks why cryolite is added during the electrolysis of alumina (Al₂O₃). 2. **Properties of Alumina**: Pure alumina has two main issues: - It is a poor conductor of electricity. - It has a very high melting point of approximately 2000 °C. ...
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