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प्रश्न
Write the name.
Metals which are amphoteric in nature.
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उत्तर
Metals which are amphoteric in nature- Aluminium (Al), zinc (Zn)
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संबंधित प्रश्न
How is copper extracted from its sulphide ore? Explain the various steps supported by chemical equations. Draw labelled diagram for the electrolytic refining of copper.
The process by which sulphide ore is concentrated.
In the extraction of aluminium: Write the function and formula of cryolite in the extraction of aluminium.
Name two metals which are highly resistant to corrosion.
Explain given equation, what happens when ZnCO3 is heated in the absence of air?
Name the chemical compound which is electrolysed in molten state to obtain aluminium metal. Which gas is evolved during this process?
Name the chemical compound which is electrolysed in molten state to obtain sodium metal. Which gas is produced in this process?
Which of the following is an iron ore?
(a) cinnabar
(b) calamine
(c) haematite
(d) rock salt
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
When an object made of metal A is kept in air for a considerable time, it loses its shine and becomes almost black due to the formation of a layer of substance B. When an object made of another metal C is kept in damp air for a considerable time, it gets covered with a green layer of substance D. Metal A is the best conductor of electricity whereas metal C is the next best conductor of electricity.
(a) What is metal A?
(b) What is metal C?
(c) Name the substance B.
(d) Name the substance D.
Give reasons, why aluminum is used in:
making alloys
Give reasons, why aluminum is used in:
wrapping chocolates
Define the term:
Flux
The following question relate to the extraction of aluminium by electrolysis.
Give the equation for the reaction which takes place at the cathode.
How is the method of extraction of metals high up in the reactivity series different from that for metals in the middle? Why can the same process not be applied for them? Name the process used for the extraction of these metals.
In electrolytic reduction of alumina _______ is used as a cathode.
In Electrolytic reduction of alumina, Anode : _______ : : Cathode : Graphite lining
The electrolysis of alumina involves the use of fluorspar and cryolite to increase the melting point.
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?
2 mL each of concentrated HCl, HNO3 and a mixture of concentrated HCl and concentrated HNO3 in the ratio of 3 : 1 were taken in test tubes labelled as A, B and C. A small piece of metal was put in each test tube. No change occurred in test tubes A and B but the metal got dissolved in test tube C respectively. The metal could be
