Sulfuric Acid - H₂SO₄

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What is Sulfuric Acid?

Sulfuric acid is defined as a strong acid with oxidizing and hygroscopic properties. Sulfuric Acid is also a mineral acid having the chemical formula H2SO4.

About Sulfuric Acid

Sulfuric acid is also called either Oil of vitriol or Mattling acid. It holds a strong acidic nature, and it is corrosive. At higher concentrations, this compound acts as a dehydrating agent and oxidizing agent. It is a syrupy liquid which is colourless with no odour. It releases heat when dissolved in water, and it is water-soluble. It can be widely used in fertilizer manufacturing. Also, it can be used in wastewater processes and in chemical synthesis.

Anhydrous sulfuric acid contains a dielectric constant of around 100, and it is a polar liquid and perhaps the most essential heavy industrial chemical, with large-scale uses in a wide range of industries.

H2SO4 Structure

Let us look at the sulfuric acid structure, which is represented as follows:

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Properties of Sulfuric Acid – H2SO4

Physical Properties of Sulfuric Acid


1.84 g/cm³




1.84 g/cm³

Melting Point

10 °C

Boiling Point

337 °C

Chemical Properties of Sulphuric Acid

Because the hydration reaction of the sulfuric acid is highly exothermic, the dilution should always be performed by adding the acid to the water rather than adding water to the acid. Because the reaction is in an equilibrium that favours the rapid protonation of water, the addition of acid to water ensures that the acid becomes the limiting reagent. This reaction is the best though for the production of hydronium ions:

H2SO4 + H2O → H3O+ + HSO−4 Ka1 ≈ 103 (which is a strong acid)

HSO−4 + H2O → H3O+ + SO2−4 Ka2 = 1.0×10−2 [18]

Here, HSO−4 is given as the bisulfate anion, whereas, SO2−4 is given as the sulfate anion. And, Ka1 and Ka2 are the constants of acid dissociation.

Because sulfuric acid hydration is thermodynamically favourable and its affinity for water is sufficiently strong, sulfuric acid is known to be an excellent dehydrating agent. The concentrated sulfuric acid contains a very powerful dehydrating property, by removing water (H2O) from the other chemical compounds with sugar and other carbohydrates and forming heat, steam, and carbon.

Different Reactions of Sulfuric Acid

Reactions with Metals

Even the dilute sulfuric acid reacts with several metals through a single displacement reaction with the other typical acids, forming hydrogen gas and salts (which are the metal sulfate). It attacks the reactive metals (it means, the metals at positions above the copper in the reactivity series) like aluminium, iron, zinc, magnesium, nickel, and manganese.

Fe + H2SO4 → H2 + FeSO4

Reactions with Carbon

Sulfuric acid (hot concentrated) oxidizes carbon (as bituminous coal) and sulfur. The chemical reaction can be given as follows:

C + 2 H2SO4 → CO2 + 2 SO2 + 2 H2O

Reaction with Sodium Chloride

This compound reacts with sodium chloride and produces sodium bisulfate and hydrogen chloride. The chemical reaction for this can be given as follows:

NaCl + H2SO4 → NaHSO4 + HCl

H2SO4 Uses (Sulfuric Acid)

  • It is used in steel and iron and production

  • It is used in fertilizer manufacturing

  • It is also used in chemical manufacturing industries

  • It is used to form phosphoric acid

  • It is used in petroleum refining industries

  • It is used as a catalyst to convert the cyclohexanone oxime into caprolactam, which is used to make nylon

  • In industries, it used as a cleaning agent to remove the rust from iron and steel

  • It is used in preparing ammonium sulfate

  • It is used as an electrolyte in the lead-acid batteries 

  • It is used in storage batteries

Domestic Uses

At high concentrations, sulfuric acid is frequently the primary ingredient in the acidic drain cleaners, which can be used to remove grease, tissue paper, and hair. Same as to their alkaline versions, such drain openers, dissolve proteins and fats via hydrolysis. However, as the concentrated sulfuric acid contains a strong dehydrating property, it removes tissue paper through the dehydrating process too. Since the acid can vigorously react with water, such acidic drain openers should be slowly added into the cleaned pipe.


Sulfuric acid is capable of causing severe burns, especially when this compound is at high concentrations. In common with the other alkali and corrosive acids, it readily decomposes lipids and proteins through the amide and ester hydrolysis upon contact with the living tissues, such as flesh and skin.

In addition, it also exhibits a strong dehydrating property on carbohydrates by liberating extra heat and also causing secondary thermal burns. Accordingly, it attacks the cornea if splashed onto the eyes rapidly and induces permanent blindness. If it is ingested, it damages our internal organs irreversibly and can even be fatal. Hence, protective equipment should be used when handling them. Also, its strong oxidizing property makes it highly corrosive to several metals and can cause extensive destruction on other materials.

FAQs (Frequently Asked Questions)

1. What is the World’s Strongest Acid?

Answer: Carborane superacids are considered the strongest solar acid across the world because fluoroantimonic acid is a mixture of hydrofluoric acid and pentafluoride antimony in reality.

2. What is Sulfuric Acid Used For?

Answer: The major application of sulfuric acid is in fertilizer processing, for example, ammonium sulfate and lime superphosphate. 

Commonly, it can be used in chemical processing, for example, in the manufacturing of different compounds such as nitric acid, hydrochloric acid, synthetic detergents, sulfate salts, pigments & dyes, medicines, and explosives.

3. Is it Possible to Neutralize Sulfuric Acid With Water?

Answer: When we have some amount of conc. sulphuric acid, we should pour it into the solution of sodium hydroxide. Then, the water will dilute and carry off some amount of heat that either the bicarbonate or sodium carbonate produces when it neutralizes the acid.

4. How to Neutralize Sulfuric Acid?

Answer: Pour the baking soda into an acid spill. This will neutralize the light acids like vinegar, or even toxic, and strong acids such as sulphuric and muriatic acids. Douse with baking soda (such as NaHCO3, sodium bicarbonate) in the total contaminated region to neutralize the acid.

5. Is Sulfuric Acid Molecular or Ionic?

Answer: Water forms a compromise between H3O+, H2O and -OH, which does not make anything ionic. Sulfuric acid is given as a compound with covalent bonds since the total bonds are covalent. The fact is, it ionizes readily insignificant to debate.