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Water vapours are adsorbed by:
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Adsorption is accompanied by:
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The phenomenon in which adsorption and absorption take place simultaneously is called ____________.
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Metals which occur in their native state in nature:
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Metal which is found in free state is:
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Which among the following statement is correct?
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The most abundant metal on earth is:
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The sulphide ore of iron is ____________.
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Carbonate ore of iron is ____________.
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The existence of a substance in more than one solid modifications is known as ____________.
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Which of the following is not a characteristic property of solids?
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Which of the following is not a characteristic of a crystalline solid?
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Which of the following conditions favours the existence of a substance in the solid state?
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Match the items given in Column I with the items given in Column II.
| Column I | Column II |
| (i) Mg in solid state | (a) p-Type semiconductor |
| (ii) MgCl2 in molten state | (b) n-Type semiconductor |
| (iii) Silicon with phosphorus | (c) Electrolytic conductors |
| (iv) Germanium with boron | (d) Electronic conductors |
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Why does the white precipitate of silver halide become coloured in the presence of dye eosin.
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When copper ore is mixed with silica, in a reverberatory furnace copper matte is produced. The copper matte contains ______.
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Which of the following options are correct?
(i) Cast iron is obtained by remelting pig iron with scrap iron and coke using hot air blast.
(ii) In extraction of silver, silver is extracted as cationic complex.
(iii) Nickel is purified by zone refining.
(iv) Zr and Ti are purified by van Arkel method.
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In the extraction of aluminium by Hall-Heroult process, purified \[\ce{Al2O3}\] is mixed with \[\ce{CaF2}\] to:
(i) lower the melting point of \[\ce{Al2O3}\].
(ii) increase the conductivity of molten mixture.
(iii) reduce \[\ce{Al^{3+}}\] into \[\ce{Al(s)}\].
(iv) acts as catalyst.
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Which of the following reactions occur during calcination?
(i) \[\ce{CaCo3 -> CaO + CO2}\]
(ii) \[\ce{2FeS2 + 11/2 O2 -> Fe2O3 + 4SO2}\]
(iii) \[\ce{Al2O3. {x}H2O -> Al2O3 + {x}H2O}\]
(iv) \[\ce{ZnS + 3/2 O2 -> ZnO + SO2}\]
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The main reactions occurring in blast furnace during extraction of iron from haematite are:
(i) \[\ce{Fe2O3 + 3CO -> 2Fe + 3CO2}\]
(ii) \[\ce{FeO + SiO2 -> FeSiO3}\]
(iii) \[\ce{Fe2O3 + 3C -> 2Fe + 3CO}\]
(iv) \[\ce{CaO + SiO2 -> CaSiO3}\]
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