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

Magnesium (Mg), an alkaline earth metal, is highly reactive, and H2SO4 (sulfuric acid) is a strong inorganic acid. Let us examine their reaction in detail.

The reaction between Mg and H2SO4 is highly vigorous. Magnesium is a reactive metal that exists in +2 oxidation state in its ionic form, is found in chlorophyll pigment, and plays a vital role in the proper functioning of the human body. H2SO4 is a strong dehydrating agent.

Here, we will discuss the reaction products, forces involved, buffer solution, and other parameters of H2SO4 and Mg deeply.

What is the product of H2SO4 and Mg

MgSO4 (Magnesium sulfate) and hydrogen gas are the products of the reaction H2SO4 + Mg.

H2SO4 + Mg → MgSO4 + H2

What type of reaction is H2SO4 + Mg

H2SO4 + Mg is a single displacement reaction.

How to balance H2SO4 + Mg

The equation H2SO4 + Mg is balanced through the following steps

 H2SO4 + Mg → MgSO4 + H2

Elements involvedReactants sideProducts side
Count of the elements
  • The elements involved in the reaction are identified and counted. Mg, H, S, and O are the elements that are present in the substituents.
  • Here the elements are balanced both in the reactant and product side. Thus the balanced equation is
  • H2SO4 + Mg → MgSO4 + H2

H2SO4 + Mg titration

H2SO4+Mg will not undergo titration as Mg being a metal will not be used in the titration.

H2SO4 + Mg net ionic equation

The net ionic equation of H2SO4+Mg is

2H+ (aq) + Mg(s) → Mg2+(aq) + SO42-(aq)+ H2(g)

The net equation is derived using the given steps

  • The balanced equation deduced earlier is written.
  • H2SO4 + Mg → MgSO4 + H2
  • The states of the reactants and the products are shown.
  • H2SO4(aq) + Mg(s) → MgSO4(aq)+ H2(g)
  • The electrolytes(strong) are split into their respective ions. Mg is a solid and H2 is a gas so will not split. The equation now becomes
  • 2H+ (aq) +SO42-(aq) + Mg(s) → Mg2+(aq) + SO42-(aq)+ H2(g)
  • The spectator ions are canceled out and the net ionic equation is
  • 2H+ (aq) + Mg(s) → Mg2+(aq) + SO42-(aq)+ H2(g)

H2SO4 + Mg conjugate pairs

H2SO4 + Mg is not a conjugate pair as they do not conjugate to form the desired acid-base pair.

  • SO42- is the conjugate base of H2SO4 (acid).
  • Mg is metal so there is no conjugate pair for Mg.

H2SO4 and Mg intermolecular forces

  • Hydrogen bonding, dispersion forces, and dipole-dipole interactions are the intermolecular forces found in the H2SO4 molecule.
  • Metallic bonding is present in Mg as it is a metal.

H2SO4 + Mg reaction enthalpy

H2SO4 + Mg reaction enthalpy is -466.85 KJ. The enthalpy will be calculated using the values listed below,

Reaction and productsEnthalpy in KJ
Enthalpy values
  • The enthalpy of the elements or the molecule present in their original state is taken as zero.
  • ∆Hf°(reaction) = ∆Hf°(products) – ∆Hf°(reactants)

= -1376.12 – (-909.27)

= -466. 85 KJ

Is H2SO4 + Mg a buffer solution

The combination H2SO4 + Mg will not function as a buffer solution due to the presence of metal and the use of a strong acid (H2SO4).

Is H2SO4 + Mg a complete reaction

H2SO4 + Mg is a complete reaction as the products will not react further since one of them is a gas that gets evolved during the reaction.

Is H2SO4 + Mg an exothermic or endothermic reaction

H2SO4 + Mg is an exothermic reaction as a large amount is heat is liberated during the reaction. The enthalpy of the reaction is negative too.

Is H2SO4 + Mg a redox reaction

H2SO4 + Mg is a redox reaction where,

  • Magnesium is getting oxidized from zero to +2 oxidation state.
  • Hydrogen is reduced from a +1 to a zero oxidation state.

Is H2SO4 + Mg a precipitation reaction

Mg + H2SO4 is not a precipitation reaction as the products formed are completely soluble without the formation of any precipitate.

Is H2SO4 + Mg reversible or irreversible reaction

Mg + H2SO4 is an irreversible reaction as the forward reaction is more feasible due to the increase in entropy attributed to the liberation of a gaseous product.

Is H2SO4 + Mg displacement reaction

Mg + H2SO4 is a single displacement reaction as Mg is more reactive so it will displace the hydrogen from its sulfate salt and forms Magnesium sulfate.

H2SO4 + Mg → MgSO4 + H2


The reaction was found to be exothermic and with positive entropy. MgSO4 generally called as Epsom salt, has a wide application in the field of healthcare, used in magnesium deficiency and asthma. The deficiency of magnesium causes weakening of bones and muscles.