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प्रश्न
Observe the following diagram and write answers.
- Name the method.
- Write anode reaction and cathode reaction.
- Why fluorspar and cryolite are added in the mixture?
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उत्तर
- This method is electrolytic reduction of alumina.
- Anode reaction:
\[\ce{2O^{2-} -> O2 + 4e^-}\] (Oxidation)
Cathode reaction:
\[\ce{Al^{3+} + 3e^- -> Al_{(l)}}\] (Reduction) - Alumina has a very high melting point (>2000 °C). The purpose of mixing ‘cryolite’ and ‘fluorspar’ with ‘alumina’ in the electrolytic reduction of alumina is to carry out the process at a much lower temperature. Addition of cryolite and fluorspar reduces the melting point of alumina to about 1000 °C.
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संबंधित प्रश्न
In the extraction of aluminium: Draw the diagram for the extraction of aluminium.
What is meant by the ‘concentration of ore’?
Name one ore of copper (other than cuprite). Which compound of copper is present in this ore? Also, write its chemical formula.
Name one ore of sodium. Name the sodium compound present in this ore and write its chemical formula.
Describe the extraction of zinc metal from its sulphide ore (zinc blende). Write equations of the reactions involved.
Name two ores of zinc. Write the names of the chemical compounds present in them and give their chemical formulae.
The two metals which can be extracted just by heating their sulphides in air are ______.
A sulphide ore is converted into metal oxide by the process of ______.
Give the chemical formula of :
Cryolite
Answer the following questions based on the extraction of aluminium from alumina by Hall - Heroult’s Process :
Name the electrode, from which aluminium collected.
X is an element in the form of a powder. X burns in oxygen and the product is soluble in water. The solution is tested with litmus. Write down only the word which will correctly complete each of the following sentences:
(a) If X is a metal, then the litmus will turn ______.
(b) If X is a non-metal, then the litmus will turn ______.
(c) If X is a reactive metal, then ______ will be evolved, when X reacts with dilute sulphuric acid.
(d) If X is a non -metal, it will form _ oxide, which will form ______ solution with water.
(e) If X is a non -metal, it will not conduct electricity unless it is carbon in the form of ______.
Define calcination.
Atomic number of aluminium is _______ and its electronic configuration is _______.
Extraction of moderately reactive elements is done by _______ and _______ method.
Write the name.
The process of extraction of aluminium from alumina-
The electrolysis of alumina involves the use of fluorspar and cryolite to increase the melting point.
Write the molecular formulae of the following compound.
Sodium aluminate
Explain the concept of Calcination.
Explain concept with example/explain with the help of a balanced equation.
Roasting
2 mL each of concentrated HCl, HNO3 and a mixture of concentrated HCl and concentrated HNO3 in the ratio of 3 : 1 were taken in test tubes labelled as A, B and C. A small piece of metal was put in each test tube. No change occurred in test tubes A and B but the metal got dissolved in test tube C respectively. The metal could be
