Question

Arrange the steps in the contact process in a proper sequence from top to bottom.

• A. Production of ${\mathrm{SO}}_2$
• B. Oxidation of $S{O}_2$
• C. Absorption of ${\mathrm{SO}}_3$
• D. Dilution of $H_2{S}_2{O}_7$

Answer 1

Industrial production of sulphuric acid is carried out by contact process. The different stages involved in contact process are:

Step 1. Production of sulphur dioxide$\left(S{O}_2\right)$:

$S\left(g\right)+O_2\left(g\right)\to S{O}_2\left(g\right)$

Step 2. Oxidation of $S{O}_2$:

$2{\mathrm{SO}}_2\left(g\right)+O_2\left(g\right)\underset{}{\overset{\mathrm{Vanadium}\mathrm{pentoxide}}{\to }}2{\mathrm{SO}}_3\left(g\right)$

Step 3. Absorption of $S{O}_2$ and formation of oleum $\left(H_2{S}_2{O}_7\right)$:

$S{O}_3\left(g\right)+H_{2}S{O}_4\left(aq\right)\to H_2{S}_2{O}_7\left(aq\right)$

Step 4. Dilution of $H_{2}S{O}_4$ to produce sulphuric acid:

$H_2{S}_2{O}_7\left(aq\right)+H_{2}O\left(l\right)\to 2H_{2}S{O}_4\left(aq\right)$