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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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Although carbon and hydrogen are better reducing agents but they are not used to reduce metallic oxides at high temperatures. Why?
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Write the chemical reactions involved in the extraction of gold by cyanide process. Also give the role of zinc in the extraction.
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The number of ions formed on dissolving one molecule of FeSO4.(NH4)2SO4.6H2O in water is ______.
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Write the structure of 3-methyl butanal
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What happens if external potential applied becomes greater than E°cell of electrochemical cell?
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Write two differences between an ideal solution and a non-ideal solution.
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Account for the following : Nitrogen does not form pentahalide.
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Write the structure of 2-methylbutanal.
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Why do solids have a definite volume?
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Classify the following as amorphous or crystalline solids:
Polyurethane, naphthalene, benzoic acid, teflon, potassium nitrate, cellophane, polyvinyl chloride, fibre glass, copper.
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Why is glass considered a super cooled liquid?
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