(a) `text(Lead Chamber Process :)`

`S + O_2 -> SO_2`

`FeS_2 + 2O_2 -> Fe_2O_3 + 4SO_2`

`SO_2 + NO_2 -> SO_3 + NO`

`SO_2 + H_2O -> H_2SO_4`.

`text(Note :)`

(i) `NO` (Nitric Oxide) produced takes oxygen from air and gets converted back to nitrogen dioxide. Thus oxide of nitrogen take oxygen from air and pass it to `SO_2` and thus act as oxygen carriers.

`2NO + O_2 -> 2NO_2`

(ii) It is seen that in the presence of insufficient quantity of steam or water spray, lead chamber crystals of the composition `SHSO_4`. No are obtained.

(b) `text(Contact Process :)`

`S + O_2 -> SO_2`

`FeS_2 + O_2 -> Fe_2O_3 + SO_2`

`2SO_2 + O_2 -> 2SO_3 +` Energy

Initially `Pt` was employed as catalyst but now `V_2O_5` is used because `Pt` is poisonous.

`SO_3 + text(conc.) H_2SO_4 -> H_2S_2O_7 overset(H_2O)-> undersettext(Oleum)(2H_2SO_4)`

(i) To get the appropriate amount of `H_2SO_4` contact process is utilised.

(ii) If bottle of `H_2SO_4` is opened, it absorbs unlimited amount of moisture and `H_2SO_4` overflows to conc. `H_2SO_4` is deliquescent liquid which is highly viscous and has high density.

(iii) When `H_2SO_4` is diluted by adding water the reaction being highly exothermic so temperature increases to `120^oC` and thus along with water vapour the energy released when conc. `H_2SO_4` is contacted with skin, causing burning.

(iv) Conc. `H_2SO_4 +` Glucose `-> 6C + 6H_2O`

The white sugar changes to black and this is called charring of sugar (Blackening of sugar). This is the conformation test of `H_2SO_4`.