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. $A{g}_2{C}_2$

$XC{l}_2\left(excess\right)<mspace\; width="1em"></mspace>+<mspace\; width="1em"></mspace>YC{l}_2<mspace\; width="1em"></mspace>\to <mspace\; width="1em"></mspace>XC{l}_4+Y\downarrow ;$ 

$YO<mspace\; width="1em"></mspace>\underset{>400°}{\overset{∆}{\to }}\frac{1}{2}{O}_2+<mspace\; width="1em"></mspace>Y,<mspace\; width="1em"></mspace>$

Ore of Y would be:

(a) Siderite               

(b) Cinnabar

(c) Malachite             

(d) Hornsilver

Leaching of Ag₂S is carried out by heating it with a dilute solution of:

1. NaCN only                     

2. HCl

3. NaOH                           

4. NaCN in presence of O₂

Leaching is commercially carried out for in the concentration of:

(1) Galena                           

(2) Argentite

(3) Copper pyrites               

(4) tin stone

NaCN is sometimes added in the froth flotation process as depressant when ZnS and PbS minerals are expected because:

1. $Pb{\left(CN\right)}_2$ is precipitated while no effect on ZnS

2. ZnS forms soluble complex $N{a}_2\left[Zn{\left(CN\right)}_4\right]$ while PbS forms froth

3.  PbS forms soluble complex $N{a}_2\left[Pb{\left(CN\right)}_4\right]$ while ZnS forms froth

4.  NaCN is never added in froth floatation process