Advertisements
Advertisements
प्रश्न
In the extraction of aluminium: Why is it necessary to replace anodes time to time?
Advertisements
उत्तर
The anode is replaced from time to time because it gets oxidised by oxygen which evolves at it.
APPEARS IN
संबंधित प्रश्न
Give reasons.
Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.
Name one metal which is extracted by reduction with carbon.
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.
Name two metals which are always found in combined state.
Give the name of one ore of iron. Which iron compound is present in this ore? Write its chemical formula.
Which metal is extracted from calamine 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 reasons, why aluminum is used in:
wrapping chocolates
Give the chemical formula of :
Sodium aluminate
What is meant by refining of metals? Name the three common methods used for refining.
How are metals refined by the electrolytic methods?
X is an element in the form of a powder. X burns in oxygen and the product is soluble in water. The solution is tested with litmus. Write down only the word which will correctly complete each of the following sentences:
(a) If X is a metal, then the litmus will turn ______.
(b) If X is a non-metal, then the litmus will turn ______.
(c) If X is a reactive metal, then ______ will be evolved, when X reacts with dilute sulphuric acid.
(d) If X is a non -metal, it will form _ oxide, which will form ______ solution with water.
(e) If X is a non -metal, it will not conduct electricity unless it is carbon in the form of ______.
Calcium, copper, lead, aluminium, zinc, chromium, magnesium, iron.
Choose the major metals from the list given above to make the following alloys:
(a) Stainless steel
(b) brass
Name the following:
A compound which is added to lower the fusion temperature of the electrolytic bath in the extraction of aluminium.
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.
Heating an ore in a limited supply of air or in the absence of air at a temperature just below its melting point is known as ______.
Write the name.
The process of extraction of aluminium from alumina-
In the electrolytic reduction of alumina, the lining of graphite acts as an anode.
