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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
Metallic oxides of zinc, magnesium and copper were heated with the following metals.
| Metal | Zinc | Magnesium | Copper |
| Zinc oxide | – | – | – |
| Magnesium oxide | – | – | – |
| Copper oxide | – | – | – |
In which cases will you find displacement reactions taking place?
Name a reducing agent that may be used to obtain manganese from manganese dioxide.
Silver metal does not combine easily with oxygen but silver jewellery tarnishes after some time. How?
Name two metals which occur in nature in free state as well as in combined state.
Describe with one example, how moderately reactive metals (which are in the middle of reactivity series) are extracted.
Name one ore of copper (other than cuprite). Which compound of copper is present in this ore? Also, write its chemical formula.
Name the metal which is extracted from haematite ore.
Explain how, mercury is extracted from its sulphide ore (cinnabar). Give equations of the reactions involved.
Name one ore of mercury. Which mercury compound is present in this ore? Write its chemical formula.
Calamine ore can be used to extract one of the following metals. This metal is:
(a) copper
(b) mercury
(c) aluminium
(d) zinc
The metal which can be extracted simply by heating the cinnabar ore in air is:
(a) Zn
(b) Cu
(c) Al
(d) Hg
Give reasons, why aluminum is used in:
making alloys
Name the following:
The process in which an ore is heated in air so that oxygen gets added to it to form the oxides.
Explain the following:
Galvanization protects iron from rusting.
The following question relate to the extraction of aluminium by electrolysis.
Give the equation for the reaction which takes place at the cathode.
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 ______.
Compare the properties of a typical metal and a non- metal on the basis of the following:
(a) electronic configuration
(b) nature of oxides
(c) oxidizing or reducing action
(d) conductivity of heat and electricity
Correct the following statement :
Copper reacts with nitric acid to produce nitrogen dioxide.
State three objectives achieved during the roasting of ores.
What is the difference between calcination and roasting?
Sulphide ores : Roasting : : Carbonate ores : _______
Write the name.
The molecular formula of main ore of aluminium –
Write the name.
The process of strong heating of carbonate ores in insufficient air–
Explain the reactions of nonmetals with water with the help of examples.
Explain the characteristics of ionic compounds.
Explain the difference between Bayer’s process and Hall’s process by explaining the Bayer’s process.
Which of the following metals exist in their native state in nature?
(i) Cu
(ii) Au
(iii) Zn
(iv) Ag
Which of the following metals exist in their native state in nature?
- Cu
- Au
- Zn
- Ag
