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प्रश्न
Name the following: Main ore of aluminium.
उत्तर
Bauxite (Al2O3.nH2O) is the main ore of aluminium.
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संबंधित प्रश्न
What chemical process is used for obtaining a metal from its oxide?
Name two metals which are highly resistant to corrosion.
Name one metal which is extracted by reduction with heat alone.
Define the term ore.
Explain why, an aqueous solution of sodium chloride is not used for the electrolytic extraction of sodium metal.
Name the chemical compound which is electrolysed in molten state to obtain aluminium metal. Which gas is evolved during this process?
Name three other metals which are extracted in a manner similar to sodium.
Which gas is produced during the extraction of aluminium? At which electrode is this gas produced?
An important ore of zinc metal is:
(a) calamine
(b) cuprite
(c) pyrolusite
(d) haematite
Calamine ore can be converted into zinc oxide by the process of:
(a) dehydration
(b) roasting
(c) calcination
(d) sulphonation
Zinc blende ore can be converted into zinc oxide by the process of:
(a) roasting
(b) hydrogenation
(c) chlorination
(d) calcination
In an electrolytic tank, aluminium metal is being extracted by the electrolysis of molten aluminium oxide using carbon electrodes. It is observed that one of the carbon electrodes is gradually burnt away and has to be replaced.
(a) Which carbon electrode (cathode or anode) is burnt away?
(b) Why is this carbon electrode burnt away?
Metals X and Y can be recovered from the anode mud left behind after the electrolytic refining of copper metal. The coins made of metal X look new even after several years of use but the coins made of metal Y lose their shine gradually and get blackened soon. When metal X is alloyed with a small amount of metal Y, it becomes hard and hence suitable for making ornaments. What are metals X and Y? Also state the colour of metal X.
Some metallic oxides can be reduced by hydrogen, carbon and carbon monoxide and some cannot. Explain.
Give reasons, why aluminum is used in:
In making ships
Aluminum is used in thermite welding:
what is ignition mixture?
Name the following:
The process of heating a substance very strongly in such a way that it does not combine with oxygen.
Compare the process of calcination and roasting.
What is galvanized iron.
Name the following:
A compound which is added to lower the fusion temperature of the electrolytic bath in the extraction of aluminium.
State the property of the metal being utilized in the following :
| Use of metal | Property |
| Zinc in Galvanization | |
| Aluminium in Thermite welding |
Answer the following question :
What is the difference between calcination and roasting.
Heating an ore in a limited supply of air or in the absence of air at a temperature just below its melting point is known as ______.
State three objectives achieved during the roasting of ores.
Draw a well-labelled diagram of extraction of Aluminium. Write the anode reaction in electrolytic reduction of Alumina.
Write the molecular formulae of the following compound.
Fluorspar
Explain the characteristics of ionic compounds.
Explain the following reaction with the balanced equation.
Sodium aluminate reacts with water
Explain the following reaction with the balanced equation.
Zinc sulphide is heated strongly in excess of air
Explain in brief types of extraction of highly reactive metals according to their reactivity.
Explain Bayer’s process of concentration of bauxite with a chemical equation.
Explain in brief electrolytic reduction of alumina with a neat labelled diagram.
The process in which a carbonate ore is heated strongly in the absence of air to convert it into metal oxide is called ____________.
In thermite welding a mixture of ____________ is ignited with a burning magnesium ribbon which produces molten iron metal as a large amount of heat is evolved.
Electrical wires have a coating of an insulting material. The material, generally used is
On the basis of reactivity metals are grouped into three categories:
- Metals of low reactivity
- Metals of medium reactivity
- Metals of high reactivity
Therefore metals are extracted in pure form from their ores on the basis of their chemical properties.
Metals of high reactivity are extracted from their ores by electrolysis of the molten ore.
Metals of low reactivity are extracted from their sulphide ores, which are converted into their oxides. The oxides of these metals are reduced to metals by simple heating.
(a) Name the process of reduction used for a metal that gives vigorous reaction with air and water both.
(b) Carbon cannot be used as a reducing agent to obtain aluminium from its oxide? Why?
(c) Describe briefly the method to obtain mercury from cinnabar. Write the chemical equation for the reactions involved in the process.
OR
(c) Differentiate between roasting and calcination giving chemical equation for each.
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.
