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प्रश्न
How electrolysis can be used in extraction of aluminium? Why aluminium cannot be reduced by conventional reducing agents?
उत्तर
Aluminium is extracted by the electrolysis of fused pure alumina dissolved in fused mixture of cryolite and fluorspar. This mixtures lowers the melting point of alumina and increases the electrical conductivity and the electrolysis
is carried out in an iron tank lined with gas carbon. This lining of a gas carbon serves as cathode. The anode consists of a number of carbon rods which dip in fused electrolyte. On passing electric current following reaction takes place.
At Cathode : Al+3 + 3e-→ Al
At anode : O-2 - 2e- → O
O + O → O2
Certain metal oxides are highly stable and so cannot be reduced by conventional reducing agents like coke, carbon monoxide or hydrogen. They are extracted from their oxides or salts by the electrolysis in fused state. For e.g.; metals like aluminium, sodium, potassium, magnesium, titanium, calcium etc. are extracted by this method.
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संबंधित प्रश्न
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State the electrode reaction at the anode during electrolysis of:
Fused lead bromide.
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The ions which discharge on the positive electrode during electrolysis ____________electrons. Thus, the ions are said to be _____________.
Name : A salt which is a weak electrolyte.
Choose the correct answer from the option given below:
In electrolysis of molten lead bromine anode is made up of
Choose the correct answer from the option given below:
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Identify the following reactions as either oxidation or reduction : O + 2e- → O-2
Element X is a metal with a valency 2. Element Y is a non-metal with a valency 3.
If the compound formed between X and Y is melted and an electric current passed through the molten compound, the element X will be obtained at the ______ and Y at the ______ of the electrolytic cell. (Provide the missing words).
X - \[\ce{HCl <=> H^{1+} + Cl-}\] (in solution state)
Y - \[\ce{PbBr2 <=> Pb^{2+} + 2Br^{1-}}\] (in molten state)
From the above reaction X or Y, identify the reaction which exhibit:
ionization
