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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.
Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.
Give reasons.
Carbonate and sulphide ores are usually converted into oxides during the process of extraction.
Name the gas in air which tarnishes silver articles slowly.
Name two metals which are highly resistant to corrosion.
Name one metal which is extracted by electrolytic reduction.
Why does aluminium not corrode right through?
Name the method by which aluminium metal is extracted.
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?
Name one ore of mercury. Which mercury compound is present in this ore? Write its chemical formula.
State three objectives achieved during the roasting of ores.
Name the anode, the cathode and the electrolyte used in the electrolytic refining of impure copper.
Give the chemical formula of :
Sodium aluminate
Name the following:
Two metals which are found in the free or native state.
Name the following:
The substance added to get rid of gangue in the extraction of metal.
How an ore is concentrated by froth floatation process?
Compare the process of calcination and roasting.
What is meant by refining of metals? Name the three common methods used for refining.
X is an element in the form of a powder. X burns in oxygen and the product is soluble in water. The solution is tested with litmus. Write down only the word which will correctly complete each of the following sentences:
(a) If X is a metal, then the litmus will turn ______.
(b) If X is a non-metal, then the litmus will turn ______.
(c) If X is a reactive metal, then ______ will be evolved, when X reacts with dilute sulphuric acid.
(d) If X is a non -metal, it will form _ oxide, which will form ______ solution with water.
(e) If X is a non -metal, it will not conduct electricity unless it is carbon in the form of ______.
Name the following:
The process of heating an ore to a high temperature in the presence of air.
State the property of the metal being utilized in the following :
| Use of metal | Property |
| Zinc in Galvanization | |
| Aluminium in Thermite welding |
Zinc blende is converted to oxide by ______ process.
In electrolytic reduction of alumina _______ is used as a cathode.
Explain the reactions of nonmetals with water with the help of examples.
Observe the following diagram and write answers.
- Name the method.
- Write anode reaction and cathode reaction.
- Why fluorspar and cryolite are added in the mixture?
Which of the statements about the reaction, \[\ce{ZnO + CO -> Zn + CO2}\] is correct?
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
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.
A mineral from which the metal can be extracted economically and conveniently is known as ______.
