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प्रश्न
In electrolytic reduction of alumina _______ is used as a cathode.
पर्याय
sulphur
graphite
platinum
aluminium
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उत्तर
In electrolytic reduction of alumina graphite is used as a cathode.
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संबंधित प्रश्न
Name one metal which is extracted by:
Reduction with carbon.
The non-metal present in steel is ______.
Define the term gangue.
What is meant by the ‘concentration of ore’?
Name the chemical compound which is electrolysed in molten state to obtain aluminium metal. Which gas is evolved during this process?
The two metals which can be extracted just by heating their sulphides in air are ______.
An important ore of zinc metal is ______.
Manganese metal is extracted from manganese dioxide by a reduction process by making use of ______.
Give reasons, why aluminum is used in:
making alloys
Define the following term.
Mineral
Give the chemical formula of :
Bauxite
Complete the incomplete statement with missing words:
Metals are ______ while non-metals are ______ conductors of heat.
Which one of the following is not true of metal :
Metals are good conductors of electricity.
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.
Find the odd one out and give its explanation.
Explain the reactions of nonmetals with water with the help of examples.
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 given reaction shows one of the processes to extract the metals like Iron and Manganese.
\[\ce{MnO2(s) + Al(s) -> Mn(l) + Al2O3(s) + Heat}\]
Give the reason why the above reaction is known as a thermite reaction.
