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प्रश्न
Define roasting.
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उत्तर
Roasting is the process of heating concentrated ore to a high temperature in the presence of air. The process is usually carried out for sulphide ores.
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संबंधित प्रश्न
Give reasons.
Carbonate and sulphide ores are usually converted into oxides during the process of extraction.
In the extraction of aluminium Write the cathode reaction in electrolytic reduction of alumina.
In the extraction of aluminium: Write the function and formula of cryolite in the extraction of aluminium.
A zinc ore gave CO2 on treatment with a dilute acid. Identify the ore and write its chemical formula.
Name two metals which are highly resistant to corrosion.
Why are the metals like Na, K, Ca and Mg never found in their free state in nature?
Fill in the following blank with suitable word:
The non-metal present in steel is ............
Fill in the following blank with suitable word:
The rocky material found with ores is called.............
Explain givem equation, what happens when a mixture of Cu2O and Cu2S is heated?
Name the chemical compound which is electrolysed in molten state to obtain sodium metal. Which gas is produced in this process?
What iron compound is present in haematite ore? Also write its chemical formula.
Name one ore of mercury. Which mercury compound is present in this ore? Write its chemical formula.
The metal which is always present in an amalgam is:
(a) iron
(b) aluminium
(c) mercury
(d) magnesium
Some metallic oxides can be reduced by hydrogen, carbon and carbon monoxide and some cannot. Explain.
Give reasons, why aluminum is used in:
In making ships
Aluminum is used in thermite welding:
what is thermit?
Give the chemical formula of :
Bauxite
Explain the following:
Galvanization protects iron from rusting.
Complete the incomplete statement with missing words:
Metals are ______ while non-metals are ______ conductors of heat.
Name : The metal which is liquid at room temperature.
Which one of the following is not true of metal :
Metal will have 1 or 2 or 3 electrons in their valence shell.
choose the most appropriate term to match the given description.
Heating of the ore in the absence of air to high temperature
Usually ______ ores are subjected to ______ which is done in the absence of air.
Zinc blende is converted to oxide by ______ process.
Iqbal treated a lustrous, divalent element M with sodium hydroxide. He observed the formation of bubbles in reaction mixture. He made the same observations when this element was treated with hydrochloric acid. Suggest how can he identify the produced gas. Write chemical equations for both the reactions.
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.
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 a reason why Aluminium is preferably used in thermite reactions.
A mineral from which the metal can be extracted economically and conveniently is known as ______.
