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प्रश्न
Explain the concept of Roasting.
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उत्तर
In roasting process, the sulphide ores are strongly heated in air to transform them into oxides. In this process, sulphide ores are oxidized to form metal oxides and sulphur dioxide gas.
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संबंधित प्रश्न
Give reasons.
Carbonate and sulphide ores are usually converted into oxides during the process of extraction.
A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset, but after a futile argument, the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?
Name the gas in air which tarnishes silver articles slowly.
Silver metal does not combine easily with oxygen but silver jewellery tarnishes after some time. How?
Name two metals which are highly resistant to corrosion.
Define the term ore.
Which metal is extracted from bauxite ore?
Explain how, mercury is extracted from its sulphide ore (cinnabar). Give equations of the reactions involved.
Which metal is extracted from calamine ore?
Which of the following is an ore of mercury metal?
(a) rock salt
(b) cinnabar
(c) calamine
(d) haematite
Give reasons, why aluminum is used in:
wrapping chocolates
Identify the process given in following passage and draw neat labelled diagram showing the process.
Electrolysis of molten mixture of alumina (melting point > 20000C) is done in a steel tank. The tank has a graphite lining on the inner side. This lining does the work of a cathode. A set of graphite rods dipped in the molten electrolyte works as anode. Cryolite (Na3AlF6) and fluorspar (CaF2) are added in the mixture to lower its melting point upto 10000C.
Name : The metal which is liquid at room temperature.
Choose the correct answer from the options given below:
The metal is a liquid at room temperature.
Name the methods by which concentrated ore is converted to metallic oxide.
Zinc blende is converted to oxide by ______ process.
How is the method of extraction of metals high up in the reactivity series different from that for metals in the middle? Why can the same process not be applied for them? Name the process used for the extraction of these metals.
If Cu, Fe, Zn, Al elements are arranged in increasing order of their reactivity then the correct order would be which of the following?
Explain in brief types of extraction of less reactive metals according to their reactivity.
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 the reason why the above reaction is known as a thermite reaction.
