What is the Difference Between Sulphuric Acid and Sulfonic Acid

Sulphuric acid and sulfonic acid are two acids that contain sulfur as a central atom. Acids are substances with a pH of less than 7. They taste sour, react with metals to produce hydrogen gas and neutralize bases. 

What is the difference between sulphuric acid and sulfonic acid? Sulphuric acid is an inorganic compound, whereas sulfonic acid is an organic compound.

Key Areas Covered

1. What is Sulphuric Acid  
      – Definition, Features 
2. What is Sulfonic Acid
      – Definition, Features 
3. Similarities Between Sulphuric Acid and Sulfonic Acid
      – Outline of Common Features
4. Difference Between Sulphuric Acid and Sulfonic Acid 
      – Comparison of Key Differences
5. FAQ: Sulphuric Acid and Sulfonic Acid
      – Answers to Frequently Asked Questions

Key Terms

Sulphuric Acid, Sulfonic Acid, H₂SO₄, R-SO₃H

What is Sulphuric Acid

Sulphuric acid is an inorganic compound that is a colorless, odorless, and viscous liquid. It has the chemical formula H₂SO₄. The elemental composition of sulphuric acid is hydrogen, oxygen, and sulfur. Two of these oxygen atoms are bonded to hydrogen atoms, forming hydroxyl groups, while the other two are doubly bonded to the sulfur atom. It has a strong affinity to water, which makes sulphuric acid a good dehydrating agent. It also has oxidizing properties (it can readily accept electrons from other species). Sulphuric acid has an acidic nature, and it is a strong diprotic acid (it can donate two protons per molecule). In its first ionization, it converts to hydronium ion and hydrogen sulfate ion by donating one proton. In the second ionization step, hydrogen sulfate ions form sulfate ions by donating one more proton.

Sulphuric acid is produced in a process consisting of several steps. The most common method is the contact process. Here sulfur is converted into sulfur trioxide and then to sulphuric acid.

There are many uses of sulphuric acid. sulphuric acid is widely used in the production of phosphate fertilizer. Here, sulphuric acid converts phosphate rock into a soluble form that the plants can absorb. sulphuric acid is also used as a catalyst and a dehydrating agent in various chemical reactions and in the refining process. Moreover, sulphuric acid act as the electrolyte in the lead acid batteries.

sulphuric acid is a highly corrosive liquid. When it is in contact with the eyes and skin, it may cause severe burns. Hence, sulphuric acid should be handled with care and protective equipment.

What is Sulfonic Acid

Sulfonic acid is an organic compound having a sulfonic group (-SO₃H) attached to an alkyl or aryl group. The general formula for sulfonic acids is R-SO₃H. Here, the R group represents an organic group. The sulfur atom is in a tetrahedral geometry. The S-O bonds are highly polar. This is the reason for the acidity of the substance. This liquid has a very high acidity. Sulfonic acids participate in acid-base reactions, where salt is finally produced. It is resistant to oxidation and reduction.

Sulfonic acid is used in dye synthesis, detergent production, catalysts, pharmaceuticals, and ion exchange resins. Moreover, sulfonic acid is a corrosive substance. Thus, it should be handled with care.

Similarities Between Sulphuric Acid and Sulfonic Acid

1. Both compounds contain sulfur as a central atom.
2. They are acidic in nature.
3. Both produce ions in solution, making them strong electrolytes.
4. Both molecules have polarity due to the presence of the oxygen atom.

Difference Between Sulphuric Acid and Sulfonic Acid

Definition

• Sulphuric acid is an inorganic compound that is a colorless, odorless, and viscous liquid, whereas sulfonic acid is an organic compound having a sulfonic group attached to an alkyl or aryl group.

Nature

• Sulphuric acid is an inorganic compound, whereas sulfonic acid is an organic compound.

General Formula 

• The general formula of sulphuric acid is H₂SO₄, while the general formula of sulfonic acid is R-SO₃H.

Strength

• Sulfonic acid is a strong organic acid but slightly weaker than sulphuric acid.

Production

• Sulphuric acid is produced industrially through the contact process, while sulfonic acid is typically produced through the sulfonation of organic compounds.

Conclusion

Acids are substances with a pH of less than 7. They taste sour, react with metals to produce hydrogen gas and neutralize bases. Sulphuric acid and sulfonic acid are two acids. Sulphuric acid is an inorganic acid, whereas sulphonic acid is an organic acid. This is the basic difference between sulphuric acid and sulfonic acid.

FAQ: Sulphuric Acid and Sulfonic Acid

1. Which acid is stronger than sulphuric?

Perchloric acid (HClO4) is generally considered stronger than sulphuric acid. It’s a powerful mineral acid with a higher tendency to donate protons, making it more acidic.

2. Is sulfonic acid a strong acid?

Yes, sulfonic acids are considered strong acids. They readily donate protons (H+) to the solution. This is due to the stability of the resulting sulfonate ion.

3. What is the difference between sulphuric and sulfurous acids?

Sulphuric acid (H₂SO₄) is a strong acid with sulfur in its highest oxidation state (+6), while sulfurous acid (H₂SO₃) is a weaker acid with sulfur in a lower oxidation state (+4).

4. Is sulfonic and sulphuric acid the same?

No, sulfonic and sulphuric acid are different. sulphuric acids are inorganic compounds, while sulfonic acids are organic compounds.

5. What are the disadvantages of sulfonic acid?

Sulfonic acids are corrosive and can cause severe burns. They are also harmful to inhale, potentially causing lung damage. Additionally, sulfonic acids are often expensive and difficult to handle due to their strong acidic properties.

Reference:

1. “Sulphuric Acid.” Encyclopedia Britannica. 
2. “Sulfonic Acid.” Encyclopedia Britannica. 

Image Courtesy:

1. “Sulphuric acid 96 percent extra pure” By W. Oelen – (CC BY-SA 3.0) via Commons Wikimedia
2. “FunktionelleGruppen Sulfonsäure” By MaChe (talk) – Own work (Public Domain) via Commons Wikimedia