Tag: aluminium

Questions Related to aluminium

Bauxite, diaspore and cryolite are the ore of the:

aluminium patterns and properties of metals chemistry

  1. aluminium

  2. zinc

  3. copper

  4. silver

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Correct Option: A
Explanation:

Bauxite-$Al _2O _3$

Dispore- repeating units $AlO(OH)$
Cryolite- $Na _3AlF _6$
These are ores of aluminiunm.

Aluminium, deposited as vapour on a glass, forms good mirrors, essentially because:

aluminium patterns and properties of metals chemistry

  1. the coating is much smoother

  2. it does not scratch

  3. it has better shine than silver

  4. it does not tarnish in air

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Correct Option: D
Explanation:

Aluminium, deposited as vapour on a glass, forms good mirrors because it does not tarnish in air. If it tarnishes then the mirror would not be that good. Hence due to the property of it not tarnishing in air the mirror formed are good mirrors.

Which of the following metal is protected by a layer of its own oxide?

aluminium patterns and properties of metals chemistry

  1. Silver

  2. Sodium

  3. Aluminium

  4. Iron

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Correct Option: C
Explanation:

Aluminium is reactive and reacts spontaneously with water or air to form aluminium oxide $(Al _2O _3)$, forms a stable passive layer which protects aluminium from corrosion or further oxidation.

Crystalline metal can be transformed into metallic glass by :

aluminium patterns and properties of metals chemistry

  1. alloying

  2. pressing into thin plates

  3. slow cooling of molten metal

  4. very rapid cooling of molten metal

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Correct Option: D
Explanation:

Crystalline metal can be transformed into a metallic glass by very rapid colling of molten metal. On rapid cooling of molten metal gives amorphous solid which is nothing but metallic glass.
Hence option $D$ is correct.

Duralumin is a alloy. It does not contains:

aluminium patterns and properties of metals chemistry

  1. $Al$

  2. $Cu$

  3. $Mg$

  4. $Na$

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Correct Option: D
Explanation:

Duralumin is an alloy of aluminium that has copper and contains small amounts of magnesium, manganese, iron, and silicon: its applications requiring lightness and strength, as in aeroplane construction.So sodium is not present in Duralumin.

Hence option $D$ is correct.