Sulfuric acid is the king of chemicals due to its wide range of uses in several industries. It is a well-known mineral acid also known as the oil of vitriol. It comprises three major elements; oxygen, hydrogen, and sulfur. The chemical formula of sulfuric acid is H2SO4 which is a colorless, odorless, and viscous chemical liquid.
The pure form of sulfuric acid absorbs water vapors from the air and reacts. The reaction of water and sulfuric acid is an exothermic process. During the reaction, a large amount of heat is released. That’s why it is hygroscopic in nature and it does not occur naturally on earth. Besides this, it is the best oxidant due to its dehydrating properties.
Uses of Sulphuric acid
Some of the most common uses of sulphuric acid are:
Refining of petroleum products
Sulfuric acid with 93 percent purity is used for refining petroleum products. The weaker acids are not used because they do not have such refining properties.
For example, decolorizing and deodorizing oils by removing the unsaturated hydrocarbons. Fuming sulfuric acid can be used in oil refineries for the production of colorless and odorless products of oil.
By the use of fuming acid, sulfonates are also produced known as Twitchell’s reagent.
Production of explosive materials
In order to produce explosives materials, sulfuric acid is used in two steps; First, it is used in the nitration of organic compounds, such as toluene and phenol. Secondly, it is used as a dehydrating agent.
Pickling of steel
The amount of sulfuric acid used for the pickling of steel into tinning and galvanizing is about 30,000 to 35,000 tons per month. Here concentrated sulfuric acid is used, however, it can be diluted when producing plates and galvanized wire.
In metallurgy, sulfuric acid is used for the extraction (floating) of copper, zinc, and lead from their ores. It is also used for leaching ores and waste tailing for different metals recoveries.
When a metal surface begins to rust, there is a layer of ferric sulfate that deposits on the surface of the metal. Ferric sulfate is soluble in water. This dissolution process can be catalyzed by using sulfuric acid.
Lab Reagent in a laboratory
Sulfuric acid is used as a lab reagent in acid-base titrations, water analysis, polymer testing, redox titration, etc.
Alcohols and aldehydes can be oxidized to carboxylic acids by using dilute sulfuric acid under standard conditions. Moreover, metal oxides can be oxidized by using sulfuric acid.
Alcohol when reacted with conc. sulfuric acid forms alkenes. This is due to the hygroscopic and dehydration properties of sulfuric acid.
When alcohol reacts with sulfuric acid as a catalyst, it forms esters. The significance of the use of sulfuric acid is only in acid-catalyzed esterification. This has two features, one is the initiation of the reaction by protonation of carbonyl carbon. Secondly, sulfuric acid absorbs the water formed during the reaction, and the reaction proceeds in the forward direction.
The addition polymerization reactions can be catalyzed by conc. sulfuric acid, for example, polyethylene formation, etc. Condensation polymerization is best carried out with sulfuric acid because of its dehydration properties. For example, diacids react with diols to form polyesters in the presence of sulfuric acid.
In sulphonation, sulfuric acid is used to react with alkenes or benzene to form sulfonic acids i.e. benzenesulfonic acid.
Sulfuric acid is used as a catalyst to initiate the reaction by providing an alternative (acid-catalyzed) pathway with lower activation energy.
Uses based on the Strength
Dilute sulfuric acid
It is a weaker form of sulfuric acid. It is used:
- For the production of superphosphate, ammonium sulfate, etc.
- For the sulfates of metals, such as zinc, copper, aluminum, magnesium, etc.
- In the precipitation of calcium and barium sulfates for various purposes.
- In pickling sheet of iron into galvanizing and tinning.
- For the production of metals like silver, nickel, and gold.
- In the manufacturing of galvanic and storage batteries, electroplating, etc.
- Ether and starch, syrup, and sugar can be prepared with the help of dilute sulfuric acid.
Concentrated sulfuric acid
It is the strongest form of sulfuric acid.
- It is used for purifying chemicals e.g. benzene, paraffin oil, petroleum, etc.
- This is widely used for the production of nitroglycerin, pyroxylin, nitrobenzene, picric acid, and nitro ethers.
- They are mostly used for the synthesis of fatty acids by distillation.
- There is a variety of other chemical compounds and their derivatives that can be produced by using the concentrated form of sulphuric acid.
Fuming sulfuric acid
This form of sulfuric acid is known as oleum. It is mostly used for the manufacture of materials and chemicals. These chemicals are as:
- Explosives materials
- Several organo sulfuric acids
- Mostly weaker acids
Uses based on major consumption
Several industries use sulfuric acid at a large scale for the production of various chemical compounds. Some of the most important ones are given below:
- Sulfuric acid is widely used in the production of fertilizers.
- A huge amount of sulfuric acid is used for refining petroleum products.
- Pickling of iron and steel uses sulfuric acid in larger quantities to remove the impurities and rust from the surface of the iron.
- Nitroglycerin, nitrocellulose, and celluloid can be prepared by using excessive sulfuric acid.
- Sulfuric acid is a major source in the production of chemicals that are used in further reactions and manufacturing of chemical compounds.
- The metallurgical process uses sulfuric acid in excess amounts for extraction purposes.
Uses based on Industries
These are the following industries that use sulfuric acid:
- Paper industry
- Fertilizer industry
- Medicinal industries
- Lether industry
- Textile industry
- Material industry
- Sugar industry
- Agriculture industries
- Iron and steel industry
- Chemical industries
- Cement industry
- Paint industry
- Rubber industry, etc
Why is sulfuric acid used in fertilizers?
Sulfuric acid is used in fertilizers for the production of phosphoric acid which is then used for the production of fertilizers such as phosphate fertilizers.
What is molten sulfur used for?
Molten sulfur is an amber-colored liquid. It is used for the production of sulfuric acid, rubber, metal extraction, fertilizers, etc.
Why is sulfuric acid a dehydrating agent?
Sulfuric acid is a dehydration agent as it can remove water from chemical compounds.
What is the effect of mixing sulfuric acid and nitric acid?
Dilute sulfuric acid does not react with nitric acid. Concentrated sulfuric acid can break down nitric acid into water and nitrogen dioxide. Heat is also released as the result of this reaction.
Is sulfuric acid harmful to humans?
Yes, it is harmful to humans. It can burn the skin and damage the tissue of the human body.
What happens if you mix water with sulfuric acid?
When water is mixed with sulfuric acid, the solution becomes very hot due to an exothermic reaction. A large amount of heat is released during the reaction. Concentrated sulfuric acid reacts very vigorously with water. It can be dangerous because of continuous splashing, etc. Therefore, adding acid to water is recommended, rather than, adding water to acid.
How can you clean with sulfuric acid?
Due to its anti-corrosion properties, sulfuric acid can be used as a drain cleaner. It also acts as an anti-rusting agent for removing rust from the materials.
- Uses of Sulphuric Acid By Arthur Edward Wells.
- Uses of sulfuric acid (worldofchemicals.com)
- Applications of sulfuric acid (Wikipedia.org)