The chemical composition of "slag" formed during the smelting process in the extraction of copper is:

1. Cu₂ + FeS                                    

2. FeSiO₃

3. CuFeS                                         

4. Cu₂S + FeO

The correct statement among the following is: 

Consider the following reactions at 1000 ^oC.

(I) ZnS + 1/2O₂(g)  \(\xrightarrow[]{\Delta }\)  ZnO(g);  ∆G^o = -360 kJ mol^-1
(II) Cs + 1/2O₂(g)  \(\xrightarrow[]{\Delta }\) CO(g); ∆G^o = -460 kJ mol^-1  

Choose the correct statement about the above reactions at 1000 ^oC:

1. ZnO is more stable than CO

2. ZnO can be reduced to Zn by C

3. ZnO, and CO are formed at an equal rate

4. ZnO can not be reduced to Zn by C

During extraction, copper is obtained by the reduction of cupric oxide with:

1. Cu₂S

2. SO₂

3. FeS

4. CO

Aluminium is extracted from alumina Al₂O₃ by electrolysis of a molten mixture of:

1. ${\mathrm{Al}}_2{\mathrm{O}}_3+\mathrm{HF}+{\mathrm{NaAlF}}_4$

2. ${\mathrm{Al}}_2{\mathrm{O}}_3+{\mathrm{CaF}}_2+{\mathrm{NaAlF}}_4$

3. ${\mathrm{Al}}_2{\mathrm{O}}_3+{\mathrm{Na}}_3{\mathrm{AlF}}_6+{\mathrm{CaF}}_2$

4. ${\mathrm{Al}}_2{\mathrm{O}}_3+\mathrm{KF}+{\mathrm{Na}}_3{\mathrm{AlF}}_6$

The correct statement among the following is:  

Which metal can be purified by zone refining?

1. Ni

2. Zr

3. In

4. Fe

The method of purification that is represented by the following equation is:
\(Ti(s) \ + \ 2I_{2}(g) \ \xrightarrow[]{523 \ K} \ TiI_{4}{g}\)
\(TiI_{4}(g)\ \xrightarrow[]{1700 \ K} \ Ti(s) \ + \ 2I_{2}(g)\)

1. Cupellation

2. Poling

3. Van Arkel

4. Zone refining

The fundamental principle of froth flotation process is:

Ellingham's diagram for the formation of ${\mathrm{CO}}_2$ is a straight line in the given graph. This is due to:

1. Increase in entropy during ${\mathrm{CO}}_2$ formation.

2. Decrease in entropy during ${\mathrm{CO}}_2$ formation.

3. Entropy remains constant during ${\mathrm{CO}}_2$ formation.

4. Can not be predicted.