electrolysis
filtration
reaction with H\(_2\)SO\(_4\)
precipitation
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Discussions (21)
The correct answer is:
B) electrolysis, but more specifically, the reaction with a flux, typically cryolite (Na₃AlF₆) and then electrolysis.
However, before electrolysis, the silica impurities are removed by:
Reaction with sodium carbonate or cryolite to form sodium aluminum silicate, which floats on top of the molten aluminum and is removed.
But if I had to choose from the given options:
B) electrolysis
let's explain: During the extraction of aluminum two stages are involved, the first which is the purification of BAUXITE and the other by electrolysis.
Now, in the purification of BAUXITE, the BAUXITE is heated with NaOH under pressure to form sodium aluminate (iii).Now note the ore contains impurities which are iron(iii)oxide and trioxosilicate(iv) but since the impurities, do not react with or dissolve in alkali, then they are filtered of as a sludge.
so the correct answer is FILTRATION.Hope this explanation helps. thanks
✅ Filtration
Why (simple exam explanation):
During the purification of bauxite (Bayer’s process), the ore is treated so that useful alumina dissolves, while impurities like silica remain insoluble and are removed by filtration.
So for your options:
Electrolysis ❌ (used later to extract aluminium metal)
Filtration ✅ (correct)
Reaction with H₂SO₄ ❌
Precipitation ❌
Correct answer to tick: Filtration ✔️
Why isn't precipitation the answer?
SiO2 reacts with NaOH and forms sodium silicate, which later gets precipitated out as an insoluble compound
I get that it would later be filtered out but isnt the OG reaction termed precipitation
SiO2+2NaOH→Na2SiO3+H2O???
According to multiple textbooks, the internet, and my chemistry teacher, the answer is wrong.
