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प्रश्न
Explain in brief types of extraction of less reactive metals according to their reactivity.
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उत्तर
Extraction of less reactive metals:
- Less reactive metals such as gold, silver, platinum are found in a free state in nature.
- However, the reserves of copper in the free state are very few. It is found mainly in the form of Cu2S. Copper is obtained from Cu2S ore just by heating in the air.
\[\ce{\underset{\text{sulphide}}{\underset{\text{Copper(I)}}{2Cu2S_{(s)}}} + \underset{\text{Oxygen}}{3O_{2(g)}} ->[Heat] \underset{\text{oxide}}{\underset{\text{Copper(I)}}{2Cu2O_{(s)}}} + \underset{\text{dioxide}}{\underset{\text{Sulphur}}{2SO2\uparrow}}}\]
\[\ce{\underset{\text{Copper(I) sulphide}}{Cu2S_{(s)}} + \underset{\text{Copper(I) oxide}}{2Cu2O_{(s)}} ->[Heat] \underset{\text{Copper}}{6Cu_{(s)}} + \underset{\text{Sulphur dioxide}}{SO_2\uparrow}}\] - The copper metal thus obtained can be further refined electrolytically.
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संबंधित प्रश्न
Define the Ore.
Name two metals which are found in nature in the free state.
Give reasons.
Carbonate and sulphide ores are usually converted into oxides during the process of extraction.
In the extraction of aluminium: Draw the diagram for the extraction of aluminium.
Define the term mineral.
Which of the following pair of metals exists in their native state in nature?
(a) Ag and Hg
(b) Ag and Zn
(c) Au and Hg
(d) Au and Ag
Which of the following reactants are used to carry out the thermite reaction required for welding the broken railway tracks?
(a) Al2O3 + Fe
(b) MnO2 + Al
(c) Fe2O3 + Al
(d) Cu2O + Fe
Define the term:
Flux
Define the term:
Slag
How an ore is concentrated by froth floatation process?
What is galvanized iron.
Name a non- metal that has a metallic luster and sublimes on heating.
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 ______.
Zinc blende is converted to oxide by ______ process.
Sulphide ores : Roasting : : Carbonate ores : _______
Write the name.
The process of extraction of aluminium from alumina-
Read the following passage and answer the questions.
According to the reactivity series, zinc is more reactive than iron, iron is more reactive than silver. During study of this, a student dipped the iron nails in silver nitrate solution.
- What is reactivity series?
- What will happen when iron nails are dipped in silver nitrate solution?
- Which type of reaction happens when iron metal reacts with silver nitrate solution?
- What will happen if a zinc rod is used instead of iron nail?
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?
Which of the statements about the reaction, \[\ce{ZnO + CO -> Zn + CO2}\] is correct?
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.
