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प्रश्न
Observe the figure and answer the following.
- Write the name of the method.
- What is used as anode and cathode in this method?
- Write the molecular formula and use of cryolite.
- Write anode reaction.
- Write cathode reaction.
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उत्तर
- The method shown is an electrolytic reduction of alumina.
- A set of graphite rods dipped in the molten electrolyte acts as the anode. and the graphite lining acts as a cathode.
- Molecular formula of cryolite: Na3AlF6
Use of cryolite: Addition of cryolite reduces the melting point of alumina to about 1000 °C. - Anode reaction: \[\ce{2O^2+ -> O2 + 4e^-}\]
- Cathode reaction: \[\ce{Al^3+ + 3e^- -> Al_{(l)}}\]
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संबंधित प्रश्न
Give reasons.
Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.
Why are the metals like Na, K, Ca and Mg never found in their free state in nature?
Which one of the methods given in column I is applied for the extraction of each of the metals given in column II:
| Column I | Column II |
| Electrolytic reduction | Aluminium |
| Reduction with Carbon | Zinc |
| Reduction with Aluminium | Sodium |
| Iron | |
| Manganese | |
| Tin |
Why does aluminium not corrode right through?
Name the electrode at which aluminium metal is produced.
Which of the following is an iron ore?
(a) cinnabar
(b) calamine
(c) haematite
(d) rock salt
Which of the following reactants are used to carry out the thermite reaction required for welding the broken railway tracks?
(a) Al2O3 + Fe
(b) MnO2 + Al
(c) Fe2O3 + Al
(d) Cu2O + Fe
A sulphide ore is converted into metal oxide by the process of:
(a) carbonation
(b) roasting
(c) calcination
(d) anodising
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:
Name two metals always find in combined state.
Which method of refining is used to get 99.8% pure aluminium?
What is galvanized iron.
Arrange the metals of copper, iron, magnesium, sodium and zinc in the decreasing order of reactivity.
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.
Extraction of moderately reactive elements is done by _______ and _______ method.
Explain the following reaction with the balanced equation.
Zinc sulphide is heated strongly in excess of air
Read the following passage and answer the questions.
According to the reactivity series, zinc is more reactive than iron, iron is more reactive than silver. During study of this, a student dipped the iron nails in silver nitrate solution.
- What is reactivity series?
- What will happen when iron nails are dipped in silver nitrate solution?
- Which type of reaction happens when iron metal reacts with silver nitrate solution?
- What will happen if a zinc rod is used instead of iron nail?
In extraction of copper, the flux used is ____________.
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.
