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प्रश्न
Write the molecular formulae of the following compound.
Cryolite
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उत्तर
Cryolite- Na3AlF6
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संबंधित प्रश्न
Give reasons.
Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.
In the extraction of aluminium: Draw the diagram for the extraction of aluminium.
Explain why, carbon cannot reduce oxides of sodium or magnesium.
Name one metal which is extracted by electrolytic reduction.
Which one of the methods given in column I is applied for the extraction of each of the metals given in column II:
| Column I | Column II |
| Electrolytic reduction | Aluminium |
| Reduction with Carbon | Zinc |
| Reduction with Aluminium | Sodium |
| Iron | |
| Manganese | |
| Tin |
Name two ores of zinc. Write the names of the chemical compounds present in them and give their chemical formulae.
Explain how, mercury is extracted from its sulphide ore (cinnabar). Give equations of the reactions involved.
Give the principles of the hydrolytic method.
Give reasons, why aluminum is used in:
painting electric and telegraphic poles
Give the chemical formula of :
Cryolite
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 ______.
Which one of the following is not true of metal :
Metals are good conductors of electricity.
Define calcination.
Sulphide ores : Roasting : : Carbonate ores : _______
In the electrolytic method, a layer of highly active metal is applied to a less active metal.
Explain the concept of Roasting.
Explain in brief types of extraction of highly reactive metals according to their reactivity.
Explain in brief types of extraction of less reactive metals according to their reactivity.
Oxides of moderately reactive metals like Zinc, Iron, Nickel, Tin, Copper, etc. are reduced by using:
Assertion (A): The extraction of metals from their sulphide ores cannot take place without roasting the ore.
Reason (R): Roasting converts sulphide ores directly into metals.
