Tag: chemistry

Questions Related to chemistry

In electrolytic refining, which of the following is used as an electrolyte?

chemistry production of metals refining of metals basics of metallurgy basic metallurgical processes

  1. Impure metal

  2. Pure metal

  3. Metal salt

  4. None of the above

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Correct Option: C
Explanation:

A solution of the metal salt is used as an electrolyte. Impute metal is made the anode and a thin strip of pure metal is made of cathode.

Separation of impurities from the extracted metals is generally done by __________.

chemistry production of metals refining of metals basics of metallurgy basic metallurgical processes

  1. distillation

  2. sedimentation

  3. electrolysis

  4. none of the above

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Correct Option: C
Explanation:

Separation of impurities from the extracted metals is generally done by electrolysis of impure metals.

Lead is refined by _________________.

chemistry production of metals refining of metals basics of metallurgy basic metallurgical processes

  1. electrolysis

  2. distillation

  3. oxidation

  4. none of the above

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Correct Option: A
Explanation:

Lead is refined by electrolytic method. The other metals which are also refined by this method are aluminium and copper.

Sodium metal is refined by ___________.

chemistry production of metals refining of metals basics of metallurgy basic metallurgical processes

  1. distillation

  2. electrolysis

  3. both $A$ and $B$

  4. none of the above

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Correct Option: B
Explanation:

Sodium metal is refined by electrolytic method. 

The impurities obtained after extraction of iron by reduction is called as _______.

chemistry production of metals refining of metals basics of metallurgy basic metallurgical processes

  1. mud iron

  2. pig iron

  3. dirt iron

  4. impure iron

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Correct Option: B
Explanation:

Iron obtained after extraction by reduction contains 3−4% carbon and other impurities like phosphorus, manganese etc. This is called as pig iron.

By heating pig iron in furnace it is converted to ____________.

chemistry production of metals refining of metals basics of metallurgy basic metallurgical processes

  1. wrought iron

  2. impure iron

  3. carbon iron

  4. none of the above

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Correct Option: A
Explanation:

By heating pig iron in furnace it is converted to wrought iron. It is the pure form of iron which contains carbon. It is soft, grey, tough, malleable and ductile.

Refining of metal is:

chemistry production of metals refining of metals basics of metallurgy basic metallurgical processes

  1. purification of metal

  2. concentration of metal

  3. conversion into oxides

  4. none of above

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Correct Option: A
Explanation:

Refining consists of purifying an impure material, in this case, a metal. It is to be distinguished from other processes such as smelting and calcining in that those two involve a chemical change to the raw material, whereas in refining, the final material is usually identical chemically to the original one, only it is purer.

The electrolyte used for copper refining is an acidic solution of:

chemistry production of metals refining of metals basics of metallurgy basic metallurgical processes

  1. copper chloride

  2. copper sulphide

  3. copper sulphate

  4. impure copper

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Correct Option: C
Explanation:

The purest copper is obtained by an electrolytic process, undertaken using a slab of impure copper as the anode and a thin sheet of pure copper as the cathode. The electrolyte is an acidic solution of copper sulphate. 

The purest copper is obtained by:

chemistry production of metals refining of metals basics of metallurgy basic metallurgical processes

  1. concentration process

  2. electrolytic refining

  3. pyrolysis

  4. crystallization

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Correct Option: B
Explanation:

The purest copper is obtained by an electrolytic process, undertaken using a slab of impure copper as the anode and a thin sheet of pure copper as the cathode.

For alkali metals, only electrolytic reduction is employed.

chemistry production of metals refining of metals basics of metallurgy basic metallurgical processes

  1. True

  2. False

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Correct Option: A
Explanation:

Definition of electrolytic reduction: Removal of oxygen (or decrease of its active valency in the case of a positive element) by electrical means.

The highly electropositive metals, such as the alkali and alkaline earth metals are isolated by electrolytic reduction of their fused halides, since no suitable chemical reducing agent is available and aqueous solutions could not be used due to reactive nature of these metals.
For alkali metals, only electrolytic reduction is employed.