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a year agoContributor-Level 10
4. Iron oxides are mixed with limestone and coke in order to decompose carbonates and oxidize sulfides. This mixture is then fed into the blast furnace. Many reactions take place in different temperature ranges of the blast furnace. By oxidizing impurities from cast iron in a reverberatory furnace which is lined by hematite, wrought iron or malleable iron is obtained. This is the purest form of commercial iron. This can be shown with the following reaction:
Fe2O3 + 3C → 2Fe + 3CO.
Sulfur, silicone and phosphorus are oxidized and passed into the slag and removed as impurities when limestone is added as a flux to it.
New answer posted
a year agoContributor-Level 10
3. From Ellingham diagram, we know that ΔG° (C, CO) < G° (Fe, Fe), the following reactions are:
C+ O2→CO
2Fe+O2→2FeO
Therefore, FeO can be reduced to Fe by coke.
New answer posted
a year agoContributor-Level 10
25. Option (i) Very low value of electrical conductivity in the molten state is correct since in molten state, the ionic solids possess free ions which help in the conduction of electricity. Due to the availability of these free ions the electrical conductivity of ionic compounds in molten state is found to be very high.
New answer posted
a year agoContributor-Level 10
2. Extraction of chlorine from brine is an oxidation method. The reactions involved are:
2Cl− + 2H2O → 2OH− + H2 + Cl2
For this reaction, the value of ΔG°=+422 kJ, which is positive. Using the formula ΔG°=−nE°F, we get a negative value of E° =−2.2 V.
Since, E°=−2.2 V, it would naturally require an external voltage greater than 2.2 V for the reaction to occur.
New answer posted
a year agoContributor-Level 10
24. Option (iii) (C) and (D) is correct since Iodine is a non-polar molecular solid which acts as an insulator while H2O is a hydrogen bonded molecular solid which also acts as an insulator. Whereas Mg is a metal and acts as a conductor in solid and in its molten state and TiO is also an ionic solid which acts as an insulator in solid state but acts as a conductor in molten and in aqueous solutions.
New question posted
a year agoNew answer posted
a year agoContributor-Level 10
1. Ans:
(a). According to Ellingham diagram, the reaction of CO2 is more feasible at temperatures lower than 710 K and thus it is a better reducing agent below 710 K.
While the reaction of CO is more feasible at temperatures higher than 710 K and thus it is a better reducing agent at above 710 K.
(b). According to the Ellingham diagram, the more negative the Gibbs free energy of a particular reaction the more feasible it is to carry out. Since the oxides are easier to reduce, sulfide ores are converted into oxides before reduction.
(c). To extract copper,
New answer posted
a year agoContributor-Level 10
23. Option (iii) Diamond is correct since in diamond, the carbon atoms are held together by strong covalent bonds. It is a giant molecule. Thus, it is a solid network.
New answer posted
a year agoContributor-Level 10
22. Option (i) London forces is correct since iodine molecules are nonpolar and covalent in nature. These molecules are found to be electrically symmetrical and have no dipole moment. The molecules in a crystal lattice of iodine are thus attracted together by weak London forces.
New answer posted
a year agoContributor-Level 10
21. Option (ii) a regular arrangement of constituent particles observed over a long distance in the crystal lattice is correct since the regularity of the crystalline lattice creates local environments that are the same and hence crystals exhibit sharp melting point.
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