Advertisements
Advertisements
Question
In the extraction of aluminium: Why is it necessary to replace anodes time to time?
Solution
The anode is replaced from time to time because it gets oxidised by oxygen which evolves at it.
APPEARS IN
RELATED QUESTIONS
Fill in the following blank with suitable word:
The non-metal present in steel is ............
Give the name and chemical formula of one ore of copper.
Name two metals which occur in nature in free state as well as in combined state.
Describe with one example, how moderately reactive metals (which are in the middle of reactivity series) are extracted.
How are the less reactive metals (which are quite low in the reactivity series) extracted? Explain with the help of an example.
Define the term ore.
Which of the following metals are extracted by the electrolysis of their molten chlorides?
(a) Na and Hg
(b) Hg and Mg
(c) Na and Mg
(d) Cu and Fe
Give the principles of the hydrolytic method.
State why aluminium is extracted from its oxide by electrolysis while copper, lead, iron by reducing agents and mercury and silver by thermal decomposition.
Name the ore of mercury. With the help of balanced chemical equations, explain the process of extraction of mercury from its ore.
Name the following:
The process of heating a substance very strongly in such a way that it does not combine with oxygen.
What is the difference between calcination and roasting?
How is the method of extraction of metals high up in the reactivity series different from that for metals in the middle? Why can the same process not be applied for them? Name the process used for the extraction of these metals.
In electrolytic reduction of alumina _______ is used as a cathode.
Aluminium oxide is _______ oxide.
Gold and silver are active metals.
Explain the characteristics of ionic compounds.
The highly reactive metals like Sodium, Potassium, Magnesium, etc. are extracted by the ____________.
Why should the metal sulphides and carbonates be converted to metal oxides in the process of extraction of metal from them?
