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प्रश्न
What is the difference between calcination and roasting?
Compare roasting and calcination.
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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. \[\ce{ZnCO3 -> ZnO + CO2}\] |
संबंधित प्रश्न
Name the following:
Main ore of aluminium.
M is a metal above hydrogen in the activity series and its oxide has the formula M2O. This oxide when dissolved in water forms the corresponding hydroxide which is a good conductor of electricity. In the above context, answer the following:
1) What kind of combination exists between M and O?
2)How many electrons are there in the outermost shell of M?
3) Name the group to which M belongs.
4) State the reaction taking place at the cathode.
5) Name the product at the anode.
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: Why is it necessary to replace anodes time to time?
Why does aluminium not corrode right through?
A zinc ore on heating in air forms sulphur dioxide. Describe briefly any two stages involved in the conversion of this concentrated ore into zinc metal.
How is sodium metal extracted? Explain with the help of equation of the reaction involved.
The major ore of aluminium is known as:
(a) cinnabar
(b) calamine
(c) bauxite
(d) pyrolusite
Name the ore of mercury. With the help of balanced chemical equations, explain the process of extraction of mercury from its ore.
What is meant by concentration of ores?
Which one of the following is not true of metal :
Metals form non-polar covalent compounds
Name the following:
A steel grey coloured solid non-metal.
Find the odd one out and give its explanation.
Gold and silver are active metals.
Identify who I am!
Ore of Aluminum- ______
Explain the following reaction with the balanced equation.
Chlorine dissolved in water
Explain in brief types of extraction of highly reactive metals according to their reactivity.
In extraction of copper, the flux used is ____________.
Electrical wires have a coating of an insulting material. The material, generally used is
Iqbal treated a lustrous, divalent element M with sodium hydroxide. He observed the formation of bubbles in reaction mixture. He made the same observations when this element was treated with hydrochloric acid. Suggest how can he identify the produced gas. Write chemical equations for both the reactions.
