What is Sulphuric Acid?
Sulphuric acid is an oxidizing agent, a strong mineral acid, and a dehydrating agent. Sulfuric Acid has the chemical formula H2SO4. It is manufactured using contact process. In this process, platinum was first used as a catalyst. Later vanadium oxide replaced platinum due to cost constraints.
Contact process for manufacturing of sulphuric acid:
Steps involved in the manufacturing of sulphuric acid are as stated below:
Preparation of sulfur dioxide.
Conversion of sulphur dioxide into sulfur trioxide.
Conversion of sulfur trioxide formed into concentrated H2SO4.
Step 1: Preparation of sulphur dioxide:
SO2 is prepared by burning sulphur in the presence of excess air so that the product combines with oxygen which is helpful for the next stage.
S(s) + O2 (g) → SO2(g)
Step 2: Preparation of sulphur trioxide:
Sulphur trioxide is formed when sulphur dioxide reacts with oxygen in a ratio of 1:1 at a temperature of 400°C – 450°C and a pressure of 1-2 atm in the presence of N2O5 as a catalyst. This reaction is reversible in nature.
2SO2(g) + O2(g) ⇌ 2SO3(g)
Step 3: Preparation of concentrated sulphuric acid:
The sulphur trioxide formed is first made to react with concentrated sulphuric acid. Sulphur trioxide cannot be dissolved in water directly as it leads to the formation of fog. The product obtained after this reaction is known as oleum. The oleum obtained is then dissolved in water to obtain concentrated sulphuric acid.
H2SO4 + SO3(g) → H2S2O7(l)
H2S2O7(l) + H2O(l) → 2H2SO4
Uses of sulphuric acids:
- Up to 50 % of this liquid manufactured is used in the production of phosphoric acid which is in turn used to make phosphate fertilizers.
- It is used in the manufacturing of metals such as copper, zinc etc.
- 5% of the produced acid is used in the making of fibers.
In Domestic Environments:
- Used in acidic drain cleaners.
- Due to its strong dehydrating property, it can be used to remove tissue paper.
As a Catalyst:
- Used as a catalyst in the manufacturing process of nylon.
- Used in the Manheim process in the manufacturing of HCl.
- Used in petroleum refining.
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