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प्रश्न
Aluminium is a more active metal than iron, but suffers less corrosion. Why?
उत्तर
When aluminium is exposed to atmospheric air, it combines with oxygen, and a film of aluminium oxide (Al2O3) is formed at the surface. This hard, tightly adhering film prevents corrosion.
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संबंधित प्रश्न
For bauxite, explain its significance in the extraction of aluminium.
In order to obtain 1 tonne of aluminium, the following inputs are required: 4 tonnes 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 (III) oxide. Aluminium is obtained by the electrolysis of aluminium oxide dissolved in cryolite.
- Write the formula of cryolite.
- Write down the word which correctly completes the following sentence.
By dissolving aluminium oxide in cryolite, a ______ (conducting/non-conducting) solution is produced. - Why is so much graphite required for the electrolytic process?
- Write the equation for the reaction which takes place at the cathode.
- What is cathode made up of?
In the Hall's process for extraction of aluminium, Sate the location of cathode and anode and explain what occurs at each electrode.
In order to obtain one tone of aluminium, the following inputs are required:
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.
In construction work, why is the alloy of aluminium, duralumin used rather than pure aluminium.
Aluminium is extracted from its chief ore bauxite. The ore is first purified and then the metal is extracted from it by electrolytic reduction.
Write three balanced equations for the purification of bauxite by Hall's process.
Answer the following question :
Name a metal which is found abundantly in earth's crust.
Describe the role played in the extraction of aluminum : Graphite
Write the equation for the reaction where the aluminium oxide for the electrolytic extraction of aluminium is obtained by heating aluminium hydroxide.
Explain the reason:
Why 'food containing iron salts' should not be cooked in aluminium utensils?
Name the following :
The compound formed by the reaction between calcium oxide and silica.
