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प्रश्न
Explain concept with example/explain with the help of a balanced equation.
Roasting
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उत्तर
- The process of heating of sulphide ores strongly in excess of air to convert it into respective oxide is called roasting.
- For example, zinc sulphide is heated strongly in excess of air to convert it to zinc oxide.
\[\ce{\underset{\text{Zinc sulphide}}{2ZnS_{(s)}} + 3O_{2(g)} -> \underset{\text{Zinc oxide}}{2ZnO_{(s)}} + \underset{\text{Sulphur dioxide}}{2SO_2↑}}\]
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संबंधित प्रश्न
Define the Ore.
Give reasons.
Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.
Give two uses of bronze.
Why does a new aluminium vessel lose shine so soon after use?
Why do gold ornaments look new even after several years of use?
Name one metal which is extracted by:
Reduction with heat alone.
How is zinc extracted from its carbonate ore (calamine)? Explain with equations.
In an electrolytic tank, aluminium metal is being extracted by the electrolysis of molten aluminium oxide using carbon electrodes. It is observed that one of the carbon electrodes is gradually burnt away and has to be replaced.
- Which carbon electrode (cathode or anode) is burnt away?
- Why is this carbon electrode burnt away?
A black metal oxide XO2 is used as a catalyst in the preparation of oxygen gas from potassium chlorate. The oxide XO2 is also used in ordinary dry cells. The metal oxide XO2 cannot be reduced satisfactorily with carbon to form metal X.
- Name the metal X.
- Name the metal oxide XO2.
- Which reducing agent can be used to reduce XO2 to obtain metal X?
- Name another metal which can also be extracted by the reduction of its oxide with the above reducing agent.
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?
Which method of refining is used to get 99.8% pure aluminium?
Which one of the following is not true of metal :
Metals form non-polar covalent compounds
Name the process used for the enrichment of sulphide ore.
Write the name.
The process of strong heating of carbonate ores in insufficient air–
Explain the characteristics of ionic compounds.
Explain the following reaction with the balanced equation.
Dry aluminium hydroxide is ignited at 1000 °C
Observe the following diagram and write answers.
- Name the method.
- Write anode reaction and cathode reaction.
- Why fluorspar and cryolite are added in the mixture?
Explain in brief types of extraction of highly reactive metals according to their reactivity.
- Given below are the steps for extraction of copper from its ore. Write the reaction involved.
- Roasting of copper (I) sulphide
- Reduction of copper (I) oxide with copper (I) sulphide.
- Electrolytic refining
- Draw a neat and well labelled diagram for electrolytic refining of copper
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.
