[Chemistry Class Notes] on Preparation of Sulfuric Acid Pdf for Exam

Sulphuric Acid is an Acidic chemical compound with the formula H₂SO₄. It is widely used in the industries that is why it is called the king of chemicals. Its worldwide production clearly indicates its industrial strength. In the year 2004, its world production was about 180 million tonnes. It is also known as the oil of vitriol. It is an odourless, colourless and viscous liquid that is soluble in water. Preparation of sulphuric Acid generally involves highly exothermic processes.

The study of the oil of vitriol began in ancient times. It is believed that Muhammad ibn Zakariya al-Razi was the 1st alchemist of Iran who produced Sulphuric Acid. Then in the 17th century, German-Dutch Chemist Johann Glauber prepared Sulphuric Acid by sulphur with potassium nitrate. In 1736, Doctor Joshua Ward used this method for large-scale production of Sulphuric Acid, although it was an expensive method of production. After this many other methods of production of Sulphuric Acid were also discovered but they were not economically feasible. 

Then in 1831, British vinegar merchant Peregrine Phillips patented the contact process, in which Sulphuric Acid is produced by using sulphur dioxide and oleum in presence of vanadium pentoxide as a catalyst. This method is more economically feasible than available all other methods and produces concentrated Sulphuric Acid. It is the current method of producing Sulphuric Acid on a large scale and the high concentration required for industrial processes. 

Contact Process for Manufacturing of Sulphuric Acid 

Industrially, Sulphuric Acid is produced by the reaction of water with sulphur trioxide, which is made by the chemical combination of sulphur dioxide and oxygen, either by the chamber process or the contact process.   

Steps involved in the contact process of manufacturing Sulphuric Acid are listed below–

• Preparation of sulphur dioxide 

• Oxidation of sulphur dioxide to prepare sulphur trioxide 

• Addition reaction of sulphur trioxide and Sulphuric Acid to give oleum 

• Dilution of oleum to produce concentrated Sulphuric Acid 

Preparation of Sulphur Dioxide – In the 1st step sulphur is oxidised or burned to produce sulphur dioxide. The reaction is given below –  

S_(s) + O_2(g) 🡪 SO_2(g)

Oxidation of Sulphur Dioxide to Prepare Sulphur Trioxide – Sulphur dioxide is oxidised to sulphur trioxide in presence of vanadium pentoxide as a catalyst. It is an exothermic reaction that is reversible in nature. the reaction is given below –

2SO_2(g) + O_2(g) V₂O₅ 🡪 2SO_3(g)

Addition Reaction of Sulphur Trioxide and Sulfuric Acid to Give Oleum – Sulphur trioxide is absorbed into ~98% Sulphuric Acid to form oleum which is also known as fuming Sulphuric Acid. It is an additional reaction. The reaction is given below –

SO_3(g) + H₂SO_4(I) 🡪 H₂S₂O_7(I)

Dilution of Oleum to Produce Concentrated Sulfuric Acid – Oleum is diluted with water to form concentrated Sulphuric Acid. The reaction is given below –

H₂S₂O_7(I) + H₂O_(I) 🡪 2H₂SO_4(I)

It should be noticed here that we used 1 mole of Sulphuric Acid as a reactant and produced 2 moles of Sulphuric Acid. 

It is easy to remember the explanation of the Preparation of Sulfuric Acid with emphasis on the currently used preparation method – the Contact Process. If you are looking for NCERT Solutions of Chemistry Subject log on to the website or Download the learning app. By doing so you will not only get access to free PDFs of NCERT Solutions of Chemistry but other subjects as well.