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प्रश्न
In the extraction of aluminium: Why is it necessary to replace anodes time to time?
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उत्तर
The anode is replaced from time to time because it gets oxidised by oxygen which evolves at it.
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संबंधित प्रश्न
The process by which sulphide ore is concentrated.
In the extraction of aluminium Write the cathode reaction in electrolytic reduction of alumina.
Write the composition of the alloy called bronze.
How are the less reactive metals (which are quite low in the reactivity series) extracted? Explain with the help of an example.
Name the gas produced when calamine ore is calcined.
Name one ore of sodium. Name the sodium compound present in this ore and write its chemical formula.
During galvanisation, iron metal is given a thin coating of one of the following metals. This metal is:
(a) chromium
(b) tin
(c) zinc
(d) copper
The articles made of silver metal become dark on prolonged exposure to air. This is due to the formation of a layer of its:
(a) oxide
(b) hydride
(c) sulphide
(d) carbonate
Which metal can be extracted from the following ore?
Calamine
Distinguish between ‘roasting’ and ‘calcination’. Which of these two is used for sulphide ores and why?
An element has its electron configuration as 2,8,8,2. Now answer the following questions.
a) What is the atomic number of this element?
b) What is the group of this element?
c) To which period does this element belong?
Define the following term.
Gangue
Name the following:
The process of heating a substance very strongly in such a way that it does not combine with oxygen.
Compare the properties of a typical metal and a non- metal on the basis of the following:
(a) electronic configuration
(b) nature of oxides
(c) oxidizing or reducing action
(d) conductivity of heat and electricity
Correct the following statement :
Copper reacts with nitric acid to produce nitrogen dioxide.
Which one of the following is not true of metal :
Metals are malleable and ductile
Choose the correct answer from the options given below:
The metal is a liquid at room temperature.
Answer the following question :
What is the difference between calcination and roasting.
Write the name.
The molecular formula of main ore of aluminium –
