1 |
Which of the following is not a property of aluminium. |
An efficient electrical conductor
A low density compared to other metals
Is amphoteric
Toxic to humans
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2 |
Aluminum is an active metal but does not corrode as iron does because. |
Ai does not react with O2
A protective layer of Al2 O3 forms on the metal surface
AI is harder to Oxidize than is Fe
Aluminium has a high tensile strength
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3 |
The Hall process involves the reduction of Al2O3 to aluminium by |
Carbon
Carbon monoxide
Molecular hydrogen
Electrolysis
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4 |
The role of the mineral cryolite Na2AlF6 in the Hall process for aluminum production is. |
It is the source of aluminum
it is a chemical reducing agent
It forms a slag to remove impuriteis
In the molten state, it is a solvent for alumina Al2O3
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5 |
Which of the following statement is incorrect. |
An alloy is a mixture of two or more metals
An alloy is a mixture of two or more metal and non metal elements that have metallic properties
An alloy has a fixed composition
An amalgam is an alloy containing Hg
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6 |
Aluminium does not corrode as does iron because. |
AI does not react with O2
a-protective layer of Al2O3 forms on the metal surface
AI is harder to oxidize than is Fe
Fe gives chathodic protection to AI
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7 |
The element with maximum first ionization energy is. |
B
N
O
C
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8 |
The most abundant metal in earth's crust is. |
Fe
Al
Ti
Ca
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9 |
Which of the group 13 element does not form M (III) idodie. |
Al
Ga
Ti
In
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10 |
In B2H6 molecule |
There exists a direct B-B a -bond
All the atoms are in one plane
All the B-H bonds are normal covalent bonds
There exist two bonds between the boron atoms.
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11 |
The aluminium salt commonly used to stop bleeding is |
Aluminium sulphate
Potash Alum
Aluminium chloride
Aluminium fluroide
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12 |
Which librates H2 with NaOH |
B
AI
Zn
All
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13 |
Which one of the following statements regarding BF3 is not correct. |
It is an ionic compound
It is an electron deficient compound
It is a Lewis acid
<div>It forms adducts</div>
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14 |
Anhydrous AlCl3 cannot be obtained by heating hydrated AlOI3 ,6h2o Because. |
It decomposes completely to give Al2O3
It does not lose water completely
It undergoes hydrolysis to give Al(OH)3
AlCl3 .6H2O is very stable.
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15 |
Which of the following statements is not true about potash alum. |
Its empirical formula is KAI (SO4)2 12H2O
Its aqueous solution is basic in nature
It is used in dyeing industry
On heating it melts in its water of crystallization
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16 |
When orthoboric acid is heated strongly it gives. |
B2O3
H2B3O7
HBO2
B
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17 |
When borax is strongly hented, it gives |
B2O4
Na2B4O7
NaBO2
NaBO2 + B2O3
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18 |
In the Aluminothermite process, aluminium acts as. |
An oxidizing agent
A reducing agent
A flux
A Solder
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19 |
In the electrolysis of alumina, cryolite is added to. |
Lower the melting point of alumina
Increase the electric la conductivity
Minize anodize affect
Remove impurites from alumina
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20 |
The major role of Flurospar which is added in small quantities in the electrolytic reduction alumina dissolved in fused cryolite is. |
As a catalyst
To make the fused mixture very conducting
To lower the temperature of the melt
To decreases the rate of oxidation of carbon at the anode
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