Advertisements
Advertisements
प्रश्न
In the extraction of aluminium by Hall-Heroult process, purified \[\ce{Al2O3}\] is mixed with \[\ce{CaF2}\] to:
(i) lower the melting point of \[\ce{Al2O3}\].
(ii) increase the conductivity of molten mixture.
(iii) reduce \[\ce{Al^{3+}}\] into \[\ce{Al(s)}\].
(iv) acts as catalyst.
Advertisements
उत्तर
(i) lower the melting point of \[\ce{Al2O3}\].
(ii) increase the conductivity of molten mixture.
Explanation:
\[\ce{CaF2}\] mixed with purified \[\ce{Al2O3}\] helps in lowering the melting point of \[\ce{Al2O3}\] and increases the conductivity of the molten mixture.
APPEARS IN
संबंधित प्रश्न
Write the names and chemical formulae of any one ore of zinc.
Draw neat and labelled diagram of Bessermer converter used in the extraction of copper.
Purification of aluminium by electrolytic refining is carried out by
(a)Hoope process
(b)Hall process
(c)Baeyer process
(d)Serperck process
What is the role of limestone in the extraction of iron from its oxides?
In the extraction of Al, impure Al2O3 is dissolved in conc. NaOH to form sodium aluminate and leaving impurities behind. What is the name of this process?
What is the role of silica in the extraction of copper?
Differentiate between “minerals” and “ores”.
Explain the following methods to protect metals from corrosion:
Passivation
What is the role of the following compound-
SiO2 in the extraction of copper from copper pyrites?
Describe the role of the cryolite in the extraction of aluminium from pure alumina.
Bauxite has the composition
What are the differences between minerals and ores?
Carbonate ore of iron is ____________.
The main reactions occurring in blast furnace during extraction of iron from haematite are:
(i) \[\ce{Fe2O3 + 3CO -> 2Fe + 3CO2}\]
(ii) \[\ce{FeO + SiO2 -> FeSiO3}\]
(iii) \[\ce{Fe2O3 + 3C -> 2Fe + 3CO}\]
(iv) \[\ce{CaO + SiO2 -> CaSiO3}\]
Although carbon and hydrogen are better reducing agents but they are not used to reduce metallic oxides at high temperatures. Why?
Identify a mineral for the major source of boron from the following list?
When a strip of metallic zinc is placed in an aqueous solution of copper nitrate the blue colour of the solution disappear due to formation of
Which of the following statements, about the advantage of roasting of sulphide ore before reduction is not true?
Calamine and Malachite, respectively, are the ores of ______.
