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प्रश्न
Observe the figure and answer the following.
- Write the name of the method.
- What is used as anode and cathode in this method?
- Write the molecular formula and use of cryolite.
- Write anode reaction.
- Write cathode reaction.
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उत्तर
- The method shown is an electrolytic reduction of alumina.
- A set of graphite rods dipped in the molten electrolyte acts as the anode. and the graphite lining acts as a cathode.
- Molecular formula of cryolite: Na3AlF6
Use of cryolite: Addition of cryolite reduces the melting point of alumina to about 1000 °C. - Anode reaction: \[\ce{2O^2+ -> O2 + 4e^-}\]
- Cathode reaction: \[\ce{Al^3+ + 3e^- -> Al_{(l)}}\]
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संबंधित प्रश्न
Give reasons.
Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.
Name the following:
The property possessed by metals by which they can be beaten into sheets.
Name two metals which are highly resistant to corrosion.
Name the gas evolved when cinnabar ore is roasted.
Name two metals which are always found in combined state.
The two metals which are extracted by means of electrolytic reduction of their molten salts are:
(a) magnesium and manganese
(b) iron and aluminium
(c) zinc and magnesium
(d) magnesium and aluminium
Zinc blende ore can be converted into zinc oxide by the process of:
(a) roasting
(b) hydrogenation
(c) chlorination
(d) calcination
When an object made of metal A is kept in air for a considerable time, it loses its shine and becomes almost black due to the formation of a layer of substance B. When an object made of another metal C is kept in damp air for a considerable time, it gets covered with a green layer of substance D. Metal A is the best conductor of electricity whereas metal C is the next best conductor of electricity.
(a) What is metal A?
(b) What is metal C?
(c) Name the substance B.
(d) Name the substance D.
Give the principles of the froth floatation process.
Answer the following questions based on the extraction of aluminium from alumina by Hall - Heroult’s Process :
What is the function of cryolite used along with alumina as the electrolyte?
Name the following:
The process in which an ore is heated in air so that oxygen gets added to it to form the oxides.
Explain the following:
Galvanization protects iron from rusting.
Complete the incomplete statement with missing word:
Non-metals form acidic oxides while metals form ______.
Usually ______ ores are subjected to ______ which is done in the absence of air.
Observe the given figure of reactivity series of metals and answer the following questions:
Reactivity series of metals
- Name two metals which react with water.
- Name two moderately reactive metals.
- Name the most highly reactive metal and the most less reactive metal.
Zinc sulphide : Roasting : : zinc carbonate : _______
Explain the concept of Roasting.
Which of the statements about the reaction, \[\ce{ZnO + CO -> Zn + CO2}\] is correct?
Give the reaction involved during extraction of zinc from its ore by
- roasting of zinc ore
- calcination of zinc ore
The given reaction shows one of the processes to extract the metals like Iron and Manganese.
\[\ce{MnO2(s) + Al(s) -> Mn(l) + Al2O3(s) + Heat}\]
Give a reason why Aluminium is preferably used in thermite reactions.
