Name: Members of Nitrogen Family
Uploaded: 2019-07-19
Duration: 10 min 7 s
Description: What is the group number in a periodic table? Which group number does nitrogen belong to? How many elements belong to that group? Let's learn about it in thi...

Question

Explain in detail the manufacture of sulphuric acid by contact process.

Accepted Answer

Sulphuric acid is manufactured on a large scale by the contact process. It involves the following three steps:
Step (I): Sulphur or sulphide ores are burnt in air to form ${SO}_{2}$ .
Step (II): ${SO}_{2}$ is converted into ${SO}_{3}$ in the presence of $V_{2} O_{5}$ as a catalyst.

$2 {SO}_{2} (g) + O_{2} (g) \overset{V_{2} O_{5}}{\to} 2 {SO}_{3} (g) ∆_{t} H ° = - 196.6 {kJmol}^{- 1}$
Step (III): ${SO}_{3}$ produced in the above step is absorbed on $H_{2} {SO}_{4}$ to give $H_{2} S_{2} O_{7}$ (Oleum). This oleum is then diluted to obtain $H_{2} {SO}_{4}$ of the desired concentration.

$H_{2} {SO}_{4} + {SO}_{3} \to H_{2} S_{2} O_{7} (Oleum) H_{2} S_{2} O_{7} + H_{2} O \to 2 H_{2} {SO}_{4} (Sulphuric acid)$

The second step is the key step. It is very crucial to maximise the yield of $H_{2} {SO}_{4}$ .
The above reaction is exothermic, reversible, and the forward reaction leads to a decrease in volume. So, in accordance with Le Chatelier's principle, low temperature and high pressure are the favourable conditions for maximum yield. But the temperature should not be too low since the rate of reaction will become slow.
The optimum conditions in the contact process to maximise the yield of sulphuric acid in an industrial plant is a pressure of $2$ bar and temperature around $720 K$ .

Explain in detail the manufacture of sulphuric acid by contact process.

Important Questions on p-Block Elements

Learn and Prepare for any exam you want !