Question

Discuss the theory involved in the manufacture of sulphuric acid by contact process.

Answer 1

The manufacture of sulphuric acid by contact process:
(1) Sulphur is heated in presence of oxygen to form sulphur dioxide.
$S+O_2\stackrel{\Delta }{\to }S{O}_2$

(2) Catalytic oxidation of sulphur dioxide gives sulphur trioxide .

$2S{O}_2+O_2\underset{\text{450 deg C, 1.5 to 7 atm}}{\overset{V_2{O}_5\text{Pt asbastos}}{\to }}S{O}_3$

(3) Sulphur trioxide gas is dissolved in sulphuric acid to form oleum.

$S{O}_3+H_{2}S{O}_4\to H_2{S}_2{O}_7$

(4) Oleum is diluted with water to form sulphuric acid.

$H_2{S}_2{O}_7+H_{2}O\to 2H_{2}S{O}_4$