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प्रश्न
4 tones of bauxite, 150 Kg of sodium hydroxide and 600 Kg of graphite.
The aluminium compound in bauxite is aluminium oxide and the main impurity is iron (II) oxide. Aluminium is obtained by the electrolysis of aluminium oxide dissolved in cryolite.
(a) When bauxite is treated with sodium hydroxide solution, what happens to:
(i) the aluminium oxide?
(ii) The iron (III) oxide?
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उत्तर
(i) Aluminium oxide being an amphoteric oxide reacts with sodium hydroxide solution to form soluble sodium meta aluminate.
\[\ce{\underset{\text{Alumina}}{Al2O3.2H2O} + 2NaOH + 2H2O ->\underset{\text{Sodium aluminate}}{2NaAIO2} + 3H2O}\]
(ii) Iron (III) oxide remains undissolved in the sodium hydroxide solution and settles down.
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संबंधित प्रश्न
Give appropriate scientific reasons for Zinc oxide can be reduced to zinc metal by using
carbon, but aluminium oxide cannot be reduced by a reducing agent
How is the following metallic oxide reduced? Write the equation:
Zinc oxide
Give equation for the following conversion: Aluminium hydroxide to aluminium oxide.
Name a non-metallic element which is a liquid at ordinary temperatures
With reference to the reduction of copper (II) oxide , iron (II) oxide, lead (II) oxide and magnesium oxide; place the oxides in order of increasing ease of reduction.[i.e. first write the oxide that is most difficult to reduce and at last, the oxide, that is most easily reduced.]
Write balanced equation for the following reaction:
Reduction of copper oxide by hydrogen.
What metallic property is shown by the non-metal graphite?
Name the following :
A metal oxide that can be reduced by hydrogen
- A to F below relate to the source and extraction of either zinc or aluminium:
- Bauxite
- Coke
- Cryolite
- Froth floatation
- Sodium hydroxide solution
- Zinc blende
- Write down the three letters each from the above list which are relevant to
- Zinc
- Aluminium
- Fill in the blanks using the most appropriate words from A to F.
- The ore from which aluminium is extracted must first be treated with ………………. so that pure aluminium oxide can be obtained.
- Pure aluminium oxide is dissolved in ….. to make a conducting solution.
iii. Write the formula of cryolite.
Write a balanced equation for the reduction of copper (ll) oxide by hydrogen.
