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प्रश्न
What is the difference between calcination and roasting?
Compare roasting and calcination.
Differentiate between calcination and roasting.
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उत्तर
| Roasting | Calcination | |
| (1) | The ore is heated in the excess of air. | The ore is heated in the absence of air. |
| (2) | Volatile impurities are removed as oxides (SO2, P2O5, As2O3) and the ore becomes porous and more reactive. | Moisture and organic impurities are removed and the ore becomes porous and more reactive. |
| (3) | Sulphide ores are roasted, so SO2 is given off. \[\ce{2ZnS + 3O2 ->[800^\circ-900^\circ C]2ZnO + 2SO2}\] |
Carbonate and hydrated ores are calcined and CO2 or water vapour are given off. \[\ce{ZnCO3 -> ZnO + CO2}\] |
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संबंधित प्रश्न
Name the following:
Main ore of aluminium.
Write the steps involved in the extraction of pure metals in the middle of the activity series from their carbonate ores.
In the extraction of aluminium Write the cathode reaction in electrolytic reduction of alumina.
Name two metals which are found in nature mainly in the free state (as metallic elements).
Which metal is extracted from calamine ore?
The two metals which can be extracted just by heating their sulphides in air are ______.
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Which metal can be extracted from the following ore?
Calamine
Give the principles of the hydrolytic method.
Give the principles of the froth floatation process.
Give reasons, why aluminum is used in:
making alloys
Give reasons, why aluminum is used in:
wrapping chocolates
An element has its electron configuration as 2,8,8,2. Now answer the following questions.
a) What is the atomic number of this element?
b) What is the group of this element?
c) To which period does this element belong?
Define the following term.
Gangue
Name the following:
A compound which is added to lower the fusion temperature of the electrolytic bath in the extraction of aluminium.
Name the following:
A steel grey coloured solid non-metal.
Draw a well-labelled diagram of extraction of Aluminium. Write the anode reaction in electrolytic reduction of Alumina.
Aluminium oxide is _______ oxide.
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
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