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प्रश्न
Explain the concept of Calcination.
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उत्तर
In the calcination process, carbonate ores are strongly heated in a limited supply of air to transform them into oxides. In this process, carbonate ores decompose to form a metal oxide and carbon dioxide gas.
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संबंधित प्रश्न
Name the chemical compound which is electrolysed in molten state to obtain aluminium metal. Which gas is evolved during this process?
A sulphide ore is converted into metal oxide by the process of:
(a) carbonation
(b) roasting
(c) calcination
(d) anodising
The metal which can be extracted from pyrolusite ore is:
(a) mercury
(b) manganese
(c) aluminium
(d) magnesium
Give reasons, why aluminum is used in:
In making ships
Distinguish between ‘roasting’ and ‘calcination’. Which of these two is used for sulphide ores and why?
Define the following term.
Mineral
Answer the following questions based on the extraction of aluminium from alumina by Hall - Heroult’s Process :
Why is powdered coke sprinkled on top of the electrolyte?
Name the following:
The substance added to get rid of gangue in the extraction of metal.
Complete the incomplete statement with missing word:
Metals form positive ions while non- metals ______.
Correct the following statement :
Copper reacts with nitric acid to produce nitrogen dioxide.
_______ is the least reactive metal.
Explain the reactions of nonmetals with water with the help of examples.
Complete flow chart given below.
Observe the figure and answer the following.
- Write the name of the method.
- What is used as anode and cathode in this method?
- Write the molecular formula and use of cryolite.
- Write anode reaction.
- Write cathode reaction.
Answer the questions on the following passage.
The minerals from which the metal can be separated economically are called ores. Ores contain many types of impurities such as soil, sand and rocky substances along with metal compounds. These impurities are called gangue.
Metals can be extracted from their ores by means of various methods of separation. The process of extraction of metal in a pure state from the ores is also a part of metallurgy.
Ores are taken out from the mines and the gangue is usually separated from the ore at the site itself by various methods. Then the ores are carried out to the place where metals are produced. Here metals are extracted in pure form. Then metals are further purified by different methods of purification. This entire process is called metallurgy. Most metals being reactive do not occur in nature in the free state but are found in combined state as their salts such as oxides, carbonates, sulphides, and nitrates. however, the most unreactive metals that are not affected by air, water and other natural factors like silver, gold, platinum, generally occur in a free state. The compounds of metals that occur in nature along with the impurities are called minerals.
- What are ores?
- Which processes are involved in the branch of metallurgy? What is metallurgy?
- Which metals are found in a free state?
- In what forms are metals found in combined state?
- What is gangue?
The poorest conductor of heat among metals is ____________.
The process in which a carbonate ore is heated strongly in the absence of air to convert it into metal oxide is called ____________.
Which of the statements about the reaction, \[\ce{ZnO + CO -> Zn + CO2}\] is correct?
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
