The role of cryolite in the metallurgy of aluminium is :
1. | To decrease the melting point of the mixture from 2323 K to 1140 K |
2. | To increase the electrical conductivity of |
3. | To decrease the electrical conductivity of |
4. | Both '1' and '2' |
The value of ∆fGO for the formation of is – 540 kJmol−1and that of Al2O3 is – 827 kJ mol−1. The correct statement is-
1. Cr can reduce Al2O3 to Al
2. Cr2O3 cannot reduce Al2O3 to Al
3. Al can reduce to Cr
4. Al cannot reduce to Cr
The chemical reactions taking place in the extraction of zinc from zinc blende is
1.
2.
3. Both 1 and 2
4. None of the above
The reaction that do not take place in the blast furnace during the extraction of iron is-
1. Fe2O3(s) + 3CO(g) → 2Fe3O4(s) + 3CO2(g)
2. FeO(s) + CO(g) → Fe(s) + CO2(g)
3. 2 C(s) + O2(g) → 2 CO(g)
4. None of the above