Uses, Molecular Formula and Structure of Sulfuric Acid
Its molecular mass (or molar mass) is 98.08 g/mol and its molecular formula is H2SO4. The sulphur atom and two oxygen atom present in the sulphuric acid are bonded to each other via means of double bonds while the two hydrogen and two remaining oxygen atoms are present in the form of hydroxyl groups and linked to the central sulphur atom via means of single bonds. Its structure may be represented in the following manners:
FAQs on Uses of Sulfuric Acid
1. What are the most important industrial uses of sulfuric acid?
Sulfuric acid (H₂SO₄) is often called the 'king of chemicals' due to its extensive use across various industries. Its most significant applications include:
- Fertilizer Manufacturing: Used to produce phosphate fertilizers like ammonium sulfate and superphosphate.
- Chemical Synthesis: Acts as a key reagent or catalyst in producing other chemicals like hydrochloric acid, nitric acid, and various dyes and pigments.
- Metal Processing: Employed in a process called 'steel pickling' to remove rust and other impurities from the surface of iron and steel before further processing.
- Petroleum Refining: Used to remove impurities from gasoline and other refinery products.
- Manufacturing of Rayon: Plays a crucial role in the production of rayon, a semi-synthetic fibre.
2. How is sulfuric acid used in everyday household products?
While pure sulfuric acid is highly corrosive and not used directly by consumers, it is a key ingredient in the manufacturing of many household items. It is used to produce surfactants, which are the active ingredients in detergents and soaps. Additionally, highly concentrated sulfuric acid is the main component in powerful drain cleaners, where its ability to dissolve organic materials like hair and grease helps clear blockages.
3. Why is sulfuric acid essential for the production of fertilizers?
Sulfuric acid is fundamental to modern agriculture because it converts raw materials into forms that plants can absorb. Its primary role is in the production of phosphate fertilizers. It reacts with phosphate rock to produce phosphoric acid, which is then used to create fertilizers like triple superphosphate. Furthermore, it is used to manufacture ammonium sulfate, an important nitrogen fertilizer that also provides essential sulfur to the soil.
4. What is the role of sulfuric acid in metal processing, particularly in 'steel pickling'?
In metal processing, sulfuric acid serves as a powerful cleaning agent. Its most common application is in steel pickling, which is a surface treatment step to remove impurities like rust (iron oxides) and scale from steel sheets or coils. The acid bath dissolves these impurities, leaving a clean metal surface that is essential for subsequent processes like coating, galvanizing, or painting. This ensures better adhesion and a high-quality finish on the final product.
5. How does sulfuric acid function as an electrolyte in lead-acid batteries?
In lead-acid batteries, commonly found in cars, sulfuric acid acts as the electrolyte. An electrolyte is a substance that conducts electricity when dissolved in water. Inside the battery, a chemical reaction occurs between the lead (Pb) and lead dioxide (PbO₂) plates and the sulfuric acid solution. This reaction generates a flow of electrons, producing an electric current. During discharge, the acid is consumed, and during charging, it is regenerated, allowing the battery to be reused.
6. What is the importance of sulfuric acid in the pharmaceutical industry?
In the pharmaceutical industry, sulfuric acid is not typically an ingredient in final medicines but is crucial as a catalyst, dehydrating agent, and pH regulator during the synthesis of various drugs. It is used in the manufacturing process of certain chemotherapy drugs, sulfa drugs, and other organic medicinal compounds. Its ability to facilitate specific chemical reactions makes it an indispensable tool for creating complex molecules needed for modern medicine.
7. Given its wide range of uses, what are the key safety precautions when handling sulfuric acid?
Due to its highly corrosive nature, handling sulfuric acid requires strict safety measures. It can cause severe burns upon contact with skin. When diluting the acid, it is critical to add acid slowly to water, never the other way around, to prevent a violent, exothermic reaction that can cause boiling and splashing. Proper personal protective equipment (PPE), including acid-resistant gloves, goggles, and a lab coat, is mandatory to prevent injury.
8. How does sulfuric acid's property as a strong dehydrating agent make it so versatile?
Sulfuric acid's effectiveness as a dehydrating agent is one of its most important chemical properties. It has a very strong affinity for water and can remove water molecules from other compounds. This property is exploited in:
- Esterification: It removes water to drive the reaction forward when making esters (used in fragrances and flavourings).
- Gas Drying: It is used to dry gases that do not react with it, like chlorine and sulfur dioxide.
- Organic Synthesis: It can even remove the elements of water from compounds like sugar (sucrose), leaving behind a black, porous carbon foam in a dramatic demonstration.
