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प्रश्न
Explain the concept of Roasting.
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
In the extraction of aluminium: Write the function and formula of cryolite in the extraction of aluminium.
Which metal becomes black in the presence of hydrogen sulphide gas in air?
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 |
The metal which can be extracted from the bauxite ore is:
(a) Na
(b) Mn
(c) Al
(d) Hg
Which of the following metals are extracted by the electrolysis of their molten chlorides?
(a) Na and Hg
(b) Hg and Mg
(c) Na and Mg
(d) Cu and Fe
What is meant by concentration of ores?
Explain the following:
Galvanization protects iron from rusting.
Complete the incomplete statement with missing word:
Metals form positive ions while non- metals ______.
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 ______.
Complete the following by selecting the correct option from the choices given:
The metal which does not react with water or dilute H2SO4 but reacts with concentrated H2SO4 is _________
_______ is the least reactive metal.
Identify who I am!
Ore of Aluminum- ______
Write the molecular formulae of the following compound.
Cryolite
Write the molecular formulae of the following compound.
Fluorspar
Explain the following reaction with the balanced equation.
Zinc sulphide is heated strongly in excess of air
Complete flow chart given below.
- Given below are the steps for extraction of copper from its ore. Write the reaction involved.
- Roasting of copper (I) sulphide
- Reduction of copper (I) oxide with copper (I) sulphide.
- Electrolytic refining
- Draw a neat and well labelled diagram for electrolytic refining of copper
On the basis of reactivity metals are grouped into three categories:
- Metals of low reactivity
- Metals of medium reactivity
- Metals of high reactivity
Therefore metals are extracted in pure form from their ores on the basis of their chemical properties.
Metals of high reactivity are extracted from their ores by electrolysis of the molten ore.
Metals of low reactivity are extracted from their sulphide ores, which are converted into their oxides. The oxides of these metals are reduced to metals by simple heating.
(a) Name the process of reduction used for a metal that gives vigorous reaction with air and water both.
(b) Carbon cannot be used as a reducing agent to obtain aluminium from its oxide? Why?
(c) Describe briefly the method to obtain mercury from cinnabar. Write the chemical equation for the reactions involved in the process.
OR
(c) Differentiate between roasting and calcination giving chemical equation for each.
Care must be taken while diluting concentrated nitric acid with water. Why?
