15 Facts on H2SO4 + Al2O3: What, How To Balance & FAQs

Sulphuric acid(H2SO4) is the king of acids, and aluminum oxide(Al2O3) is an amphoteric oxide. Let us elaborate on the reaction between H2SO4 and Al2O3 further in this article.

Al2O3 has various common names, such as alumina and ruby. The major use of Al2O3 is to prepare aluminium metal, which has very high thermal conductivity. In contrast, H2SO4 is prepared by the reaction of SO3 with water and is dense and colorless.

With the help of a completely balanced equation, we will discuss some more properties such as precipitation reaction, redox reaction etc.

What is the product of H2SO4 and Al2O3?

When H2SO4 reacts with Al2O3, the products formed are Al2(SO4)3 (Aluminium sulphate) and H2O (water).

Al2O3 + H2SO4 →Al2(SO4)3 + H2O

What type of reaction is H2SO4 + Al2O3?

The reaction between H2SO4 and Al2O3 is a double displacement type of reaction in which ions of H2SO4 and Al2O3 mutually exchange their positions to form products.

How to balance H2SO4 + Al2O3?

  • Write the skeleton equation for this reaction in terms of symbols and formulae.
    Al2O3 + H2SO4 → Al2(SO4)3 + H2O
  • Write the number of atoms of each element on both sides of the arrow in the above equation as follows:
ElementsNumber of atoms on the reactant sideNumber of atoms on the product side
Number of atoms of each element
  • Examine the number of atoms on both sides of the equation. 
  • Equalize the number of atoms of H and O
  • The complete balanced equation is,
    Al2O3 +3H2SO4 →Al2(SO4)3 + 3H2O

H2SO4 + AL2O3 titration

The titration of H2SO4 + Al2O3 gives no results because H2SO4 does not act as the right solution to be combined with Al2O3.

H2SO4 + Al2O3 net ionic equation

The net ionic equation for the reaction H2SO4 with Al2O3 is,

2Al(aq)+6H+(aq) →2Al3+ (aq) +3H2(g)

To deduce the net ionic equation,

  • Write the complete balanced equation.
  • Al2O3 +3H2SO4 →Al2(SO4)3 + 3H2O
  • Add the physical states of the compound along with them.
  • Al2O3 (s)+3H2SO4(aq) →Al2(SO4)3(aq) + 3H2O(l)
  • Break all the compound which are soluble in water into their respective ions.
  • 2Al + 6H+ +3SO42- → 2Al3+ + 3SO42-
  • Cross out the ions which are similar on both reactant and product side.
  • The equation left is the net ionic equation. 

H2SO4 + Al2O3 conjugate pairs

H2SO4 is a very strong acid, hence has HSO4 as its base pair whereas Al2O3 has a conjugate base which is  [Al(OH)4]– 

H2SO4 and Al2O3 intermolecular forces

  • H2SO4 has three major forces present between its molecules: London dispersion forces, dipole-dipole interaction and hydrogen bonding.
  • Al2O3 consists of an ionic bond between its molecules in which Al is a metal and O is a non-metal.

H2SO4 + Al2O3 reaction enthalpy

The enthalpy change between H2SO4 and Al2O3 is,
 ΔH = –184.7kJ.

Is H2SO4 + Al2O3 a buffer solution?

H2SO4 + Al2O3 is not a buffer solution because H2SO4 is a very strong acid; hence it will break down into ions, making it incapable of a buffer solution.

Is H2SO4 + Al2O3 a complete reaction?

The reaction between H2SO4 and Al2O3 is a complete reaction because these two products combine to form two other products.

Is H2SO4 + Al2O3 an exothermic or endothermic reaction?

Al2O3 + H2SO4 → Al2(SO4)3 + H2O is highly exothermic because heat is released, and the reaction enthalpy is positive.

Is H2SO4 + Al2O3 a redox reaction?

H2SO4 + Al2O3 is not a redox reaction because the oxidation numbers do not change throughout the reaction.

Is H2SO4 + Al2O3 a precipitation reaction?

H2SO4 + Al2O3 is not a precipitate reaction because the product formed by Al2(SO4)3 is completely soluble. Hence this reaction leaves no residue.

Is H2SO4 + Al2O3 reversible or irreversible reaction?

H2SO4 + Al2O3 is irreversible because when the reaction occurs, there is a mutual exchange of ions, and we can not get those ions back, making this reaction irreversible.

Is H2SO4 + Al2O3 displacement reaction?

H2SO4+ Al2O3 is a double displacement reaction as ions of SO4 and Al2 mutually exchange their ions.


The product formed Al2(SO4)3 is a soluble salt in the form of a white crystalline solid and is hygroscopic. It has its major use in cleaning water. Al2(SO4)3 is also a coagulating agent and is sometimes commonly known as alum or papermaker’s alum.