AP EAMCET202018 Sep 2020Evening ShiftChemistryGeneral Principles and Processes of Isolation of MetalsActual
Which statement is incorrect regarding Hall-Heroult process for metallurgy of aluminium? 1. Use of ( Na ₃ AlF ₆ ) lowers the melting point of ( Al ₂ O ₃ ) 2. Steel vessel with lining of carbon acts as cathode. 3. Graphite is used as anode. 4. Carbon dioxide gas is generated at cathode.
Options
- A1
- B2
- C3
- D4
Correct answer
D. 4
Step-by-step solution
In Hall-Heroult process for extraction of aluminium (crude) from alumina ( ( Al ₂ O ₃ ) ). Statements (1), (2) and (3) are correct because cryolite ( ( Na ₃ AlF ₆ ) ) is added to ( Al ₂ O ₃ ) to lower, its melting point. Here, steel vessel with lining of carbon acts as cathode and graphite acts as anode, but statement (4) is incorrect because ( Al ) gets deposited at cathode.