Advertisements
Advertisements
प्रश्न
Write the name.
The molecular formula of main ore of aluminium –
उत्तर
The molecular formula of main ore of aluminium – Al2O3•nH2O
APPEARS IN
संबंधित प्रश्न
In the extraction of aluminium: Name the process of concentration of bauxite.
In the extraction of aluminium: Draw the diagram for the extraction of aluminium.
In the extraction of aluminium: Why is it necessary to replace anodes time to time?
Give two uses of bronze.
How is manganese extracted from manganese dioxide, MnO2? Explain with the help of an equation.
What is meant by the 'concentration of ore'?
Name the gas evolved when cinnabar ore is roasted.
Name two metals which are found in nature mainly in the free state (as metallic elements).
Give the name of one ore of iron. Which iron compound is present in this ore? Write its chemical formula.
Some metallic oxides can be reduced by hydrogen, carbon and carbon monoxide and some cannot. Explain.
Give the chemical formula of :
Bauxite
What is meant by concentration of ores?
What is passive iron?
Name a non- metal that has a metallic luster and sublimes on heating.
Name the following:
A compound which is added to lower the fusion temperature of the electrolytic bath in the extraction of aluminium.
Explain Bayer’s process of concentration of bauxite with a chemical equation.
The poorest conductor of heat among metals is ____________.
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.
Assertion (A): The extraction of metals from their sulphide ores cannot take place without roasting the ore.
Reason (R): Roasting converts sulphide ores directly into metals.
