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प्रश्न
Define roasting.
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उत्तर
Roasting is the process of heating concentrated ore to a high temperature in the presence of air. The process is usually carried out for sulphide ores.
संबंधित प्रश्न
Give reasons.
Carbonate and sulphide ores are usually converted into oxides during the process of extraction.
Fill in the following blank with suitable word:
The rocky material found with ores is called.............
Which one of the methods given in column I is applied for the extraction of each of the metals given in column II:
| Column I | Column II |
| Electrolytic reduction | Aluminium |
| Reduction with Carbon | Zinc |
| Reduction with Aluminium | Sodium |
| Iron | |
| Manganese | |
| Tin |
Why does aluminium not corrode right through?
Name one ore of sodium. Name the sodium compound present in this ore and write its chemical formula.
Name three other metals which are extracted in a manner similar to sodium.
Name one ore of aluminium. Name the aluminium compound present in this ore and write its chemical formula.
Which metal is extracted from bauxite ore?
Describe the extraction of zinc metal from its sulphide ore (zinc blende). Write equations of the reactions involved.
Name the metal which is extracted from the ore called 'rock salt'.
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) sodium and copper
(b) copper and aluminium
(c) potassium and zinc
(d) mercury and copper
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.
State three objectives achieved during the roasting of ores.
Give the principles of the hydrolytic method.
Name the following:
Name two metals always find in combined state.
Which method of refining is used to get 99.8% pure aluminium?
The following questions relate to the extraction of aluminium by electrolysis.
Explain why it is necessary to renew the anode periodically.
Which one of the following is not true of metal :
Metals are good conductors of electricity.
Usually ______ ores are subjected to ______ which is done in the absence of air.
_______ is the least reactive metal.
Zinc sulphide : Roasting : : zinc carbonate : _______
Find the odd one out and give its explanation.
Gold and silver are active metals.
Explain the characteristics of ionic compounds.
Explain the following reaction with the balanced equation.
Zinc sulphide is heated strongly in excess of air
Explain the following reaction with the balanced equation.
Zinc carbonate is heated strongly in limited supply of air
Explain the following reaction with the balanced equation.
Zinc oxide is treated with carbon
Which of the following metals exist in their native state in nature?
(i) Cu
(ii) Au
(iii) Zn
(iv) Ag
