Sulphide ores of metals are usually concentrated by Froth Flotation process. Which one of the following sulphide ores offers and exception and is concentrated by chemical leaching?

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

Chromium is obtained by reducing concentrated chromite ore with :

1. Red hot coke

2. Gaseous hydrogen 

3. Aluminium powder

4. Carbon monoxide  

Which is not correctly matched:

(1) spieglesian                                    : Mn+Fe+C

(2) Dow's sea water process                 :$Mg{\left(OH\right)}_2$

(3) parke's process                               :Ag

(4) liquation                                         spelter(Impure Zn

Incorrect match is :

(a) Purification of Al :Baeyer's method 

(b) polling :Reduction of $C{u}_{2}O$

(C)$FeC{r}_2{O}_4$ (chromite ore) : NaOH/N$a_2$$C{O}_3$

(d) Ag: Mac Arthur cyanideprocess 

Aluminium metal is purified by:

(1) Hoope's process           

(2) Hall's process

(3) Serpeck's process         

(4) Baeyer's process

Poling process is used for:

(1) The removal of $C{u}_{2}O$ from Cu     

(2) The removal of $A{l}_2{O}_3$ from Al

(3) The removal of $F{e}_2{O}_3$ from Fe     

(4) All of these

AgCl on fusion with sodium carbonate, gives:

1. $A{g}_{2}C{O}_3$                       

2. $A{g}_{2}O$

3. $Ag$                               

4. $A{g}_2{C}_2$

$XC{l}_2\left(excess\right) + YC{l}_2 \to XC{l}_4+Y\downarrow ;$ 

$YO \underset{>400°}{\overset{∆}{\to }}\frac{1}{2}{O}_2+ Y,$

Ore of Y would be:

(a) Siderite               

(b) Cinnabar

(c) Malachite             

(d) Hornsilver