Preparation of Sulphuric Acid

Introduction

Sulphuric acid is a colorless, thick, greasy, corrosive solution generated when sulfur trioxide dissolves in water. Sulphuric acid is utilized in batteries, fertilizers, paints, and explosives. H2SO4 is the chemical formula of sulphuric acid.

The geometric shape of sulphuric acid is tetrahedral, and it has a bond angle of 109.5 degrees. The shape can be represented as

Sulphuric acid is known by many names, some of them being "The King of Compounds" and "The Oil of Vitriol."

Physical Properties of Sulphuric Acid

Sulphuric acid has a lot of unique properties such as:

It is a viscous colorless liquid.
It is a non-volatile acid.
It is dense and easily dissolves in water.
It is an oily liquid.
Sulphuric acid is highly corrosive.
It is not flammable.

Chemical Properties of Sulphuric Acid

Because sulfuric acid's hydration energy is so significant, exothermically speaking, dilution must be done by introducing the acid to the water rather than the other way round. The introduction of acid to the water assures that the acid is the limiting reactant.
H2SO4 + H2O → H3O+ + HSO4-
Sulphuric acid can remove water from various compounds like carbohydrates and sugars, making it an excellent dehydrating agent.
C12H22O11 + H2SO4 → 12C + 11H2O + H2SO4
Sulphuric acid is capable of reacting with bases to get its sulfate.
CuO + H2SO4 → CuSO4 + H2O
Acids weaker than Sulphuric acid can be displaced from their salts.
H2SO4 + CH3COONa → NaHSO4 + CH3COOH

Process of Preparation of Sulphuric Acid
Three industrial processes can be named for the process of preparing sulphuric acid. They are:

Contact Process
Lead Chamber Process
Wet Sulphuric Acid Process (WSA)

1. Contact Process
The contact process is a current process for making concentrated sulfuric acid that is utilized by different sectors.
Sulfur dioxide and oxygen are pumped across heated V2O5, which acts as a catalyst. They combine to make sulfur trioxide, which reacts with water to form sulfuric acid.

Step 1: Sulphur dioxide production: SO2 is produced by heating sulfur and extra air, resulting in a product that mixes with oxygen, which is helpful during the next step.
S(s) + O2 (g) → SO2

Step 2: Sulphur trioxide is generated when sulfur dioxide interacts with oxygen at high temperatures ranging from 400°C–450°C and a pressure of 1-2 atm. V2O5 speeds up the reaction acting as a catalyst. In nature, this process can be broken down and reversed.
2SO2(g) + O2(g) → 2SO3

Step 3: The resulting sulfur trioxide is then used to interact with concentrated H2SO4. However, sulfur trioxide cannot be readily diluted with water because it causes fog to arise. Hence, oleum is produced, which is the result of this reaction.
After that, the oleum is mixed in water to create concentrated sulphuric acid.
H2SO4 + SO3(g) → H2S2O7
H2S2O7 (l) + H2O(l) → 2H2SO4 [Final Product]

Lead Chamber Process
The lead-chamber method uses nitrogen oxide of the gaseous form to produce sulfur dioxide in the damp air. The process is mainly carried out in a series of huge compartments made of lead. The role of NO in this situation is to speed up the reaction pace.
There are three stages in the process.

Glover Tower
Lead Chamber
Gay-Lussac Tower
Glover Tower is a giant structure located before the chambers in the sulfuric acid chamber process. It reduces the temperature of the heated combination of sulfur dioxide and oxygen on its route to the chambers and provides water vapor.
The lead Chamber process involves the reaction of Sulphur dioxide and oxygen in a catalyst, nitrogen dioxide, to produce Sulphur trioxide. The SO3 reacts with water to produce Sulphuric acid.
The last stage is the Gay-Lussac tower, where the gasses are flushed with cooled, concentrated acid and allowed to release nitrous vitriol which is helpful in the Glover Tower. However, the lead chamber process has largely been replaced by the more modern and efficient contact process.

Wet Sulphuric Acid Process (WSA)
Wet gas catalysis is used in the WSA method. Evaporation of a moist process gas produces concentrated sulfuric acid. The sulfuric acid is gathered in the lower portion of the WSA condenser, where it is chilled and transferred to storage, while the pure gas leaves at the top.

Uses of Sulphuric Acid

It is a type of oxidizing agent.
It has been utilized in the oil refining process.
It is used to make a variety of compounds, dyes, pharmaceuticals, among other things.
It is used in the preparation of ammunition.
It is utilized in the production of fertilizers.