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प्रश्न
Extraction of moderately reactive elements is done by _______ and _______ method.
पर्याय
roasting and calcination
roasting and reduction
separation and calcination
none of these
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उत्तर
Extraction of moderately reactive elements is done by roasting and calcination method.
संबंधित प्रश्न
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.
Which gas is produced during the extraction of aluminium? At which electrode is this gas produced?
Give the name of one ore of iron. Which iron compound is present in this ore? Write its chemical formula.
The articles made of silver metal become dark on prolonged exposure to air. This is due to the formation of a layer of its:
(a) oxide
(b) hydride
(c) sulphide
(d) carbonate
Aluminum is used in thermite welding:
what is thermit?
Give the chemical formula of :
Bauxite
Name the following:
The substance added to get rid of gangue in the extraction of metal.
Explain the following:
Galvanization protects iron from rusting.
To protect iron from rusting, it is coated with a thin layer of zinc. Name the process.
Answer the following question :
What is the difference between calcination and roasting.
Heating an ore in a limited supply of air or in the absence of air at a temperature just below its melting point is known as ______.
Carbon cannot reduce the oxides of sodium, magnesium, and aluminum to their respective metals. Why? Where are these metals placed in the reactivity series? How are these metals obtained from their ores? Take an example to explain the process of extraction along with chemical equations.
Iron is _______.
_______ is the least reactive metal.
Sulphide ores : Roasting : : Carbonate ores : _______
In the electrolytic method, a layer of highly active metal is applied to a less active metal.
Explain the following reaction with the balanced equation.
Dry aluminium hydroxide is ignited at 1000 °C
Explain concept with example/explain with the help of a balanced equation.
Roasting
In thermite welding a mixture of ____________ is ignited with a burning magnesium ribbon which produces molten iron metal as a large amount of heat is evolved.
