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प्रश्न
Explain concept with example/explain with the help of a balanced equation.
Calcination
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उत्तर
- The process of heating carbonate ores in limited air to convert it into respective oxide is called calcination.
- For example, zinc carbonate is heated strongly in a limited supply of air to convert it to zinc oxide.
\[\ce{\underset{\text{Zinc carbonate}}{ZnCO_{3(s)}} ->[Heat] \underset{\text{Zinc oxide}}{ZnO_{(s)}} + \underset{\text{Carbon dioxide}}{CO_2\uparrow}}\]
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संबंधित प्रश्न
Name the gas in air which tarnishes silver articles slowly.
Name one metal which is extracted by reduction with heat alone.
Which metal is extracted from cinnabar ore?
The metal which is always present in an amalgam is:
(a) iron
(b) aluminium
(c) mercury
(d) magnesium
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.
Which metal can be extracted from the following ore?
bauxite
Give the principles of the hydrolytic method.
State one observation for each of the following :
Copper sulphate solution is electrolysed using copper electrodes.
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?
Name the following:
The substance added to get rid of gangue in the extraction of metal.
What is meant by refining of metals? Name the three common methods used for refining.
Name:
The allotrope of the non-metal carbon which conducts electricity.
Arrange the metals of copper, iron, magnesium, sodium and zinc in the decreasing order of reactivity.
Which one of the following is not true of metal :
Metals are malleable and ductile
Name the methods by which concentrated ore is converted to metallic oxide.
What is the difference between calcination and roasting?
In electrolytic reduction of alumina _______ is used as a cathode.
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?
Explain in brief types of extraction of highly reactive metals according to their reactivity.
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.
