15 Facts on H2SO4-HGO: What, How To Balance & FAQs

Sulphuric acid reacts with mercury oxide forms white monoclinic crystals along with hydrogen oxide. Let us in detail study the reaction.

Sulfuric acid is a colorless, odorless, viscous liquid, miscible in water. It is a crucial commodity and industrial chemical, produced from different methods such as the lead chamber process, contact process, etc. Mercury oxide is used in the production of mercury and as a substance for cathodes in mercury batteries.

The reaction of H2SO4 and HgO is examined to assess their potential in industrial manufacture. The reaction is further investigated for the following chemical reactivity’s.

What is the product of H2SO4 and HgO?

Mercury oxide (HgO) reacts with Sulfuric acid (H2SO4) to form mercuric sulfate (HgSO4) and water (H2O).

H2SO4 + HgO → H2O + HgSO4        

What type of reaction is H2SO4 + HgO?

H2SO4 + HgO is a double displacement and endothermic reaction.

How to balance H2SO4 + HgO?

The steps followed to balance a chemical reaction are:

  • Write down the unbalanced chemical as:
  • HgO + H2SO4 → H2O + HgSO4        
  • Tabulate down the number of moles as shown below :
Number of moles on either side of the reaction.
  • A chemical reaction is balanced when the number of moles on the left hand side of the arrow is equal to the number of moles on the right hand side of the arrow.
  • Here moles of each elements are balanced on either side.
  • The Balanced chemical reaction is
  • HgO + H2SO4 → H2O + HgSO4
Balanced Chemical Reaction

H2SO4 + HgO titration

H2SO4 + HgO titration cannot be performed because it is not an acid base reaction.

H2SO4 + HgO net ionic equation

The net ionic equation is – HgO(s) + 2H+(aq) = H2O(l) + Hg2+(aq)

Following steps are to be followed:

  1. Firstly, the phase/state of each element is determined as shown below:
  2. HgO(s) + H2SO4(aq) = H2O(l) + HgSO4(aq)
  3. Secondly, the ionic compounds are separated into their respective ions, which is defined as the complete ionic equation–
  4. HgO(s) + 2H+(aq) + SO42-(aq) = H2O(l) + Hg2+(aq) + SO42-(aq)
  5. The common ions present on either side of the arrows are removed.
  6. HgO(s) + 2H+(aq) + SO42-(aq) = H2O(l) + Hg2+(aq) + SO42-(aq)
  7. Finally, the net ionic equation includes only the compound which are taking place in the reaction.
  8. The net ionic equation is –
  9. HgO(s) + 2H+(aq) = H2O(l) + Hg2+(aq)

H2SO4 + HgO conjugate pairs

The conjugate acid-base pairs for H2SO4 + HgO are,

  • Conjugate acid of H2SO4 =  H3O+
  • Conjugate base of H2SO4  = HSO4 
  • Conjugate acid of HgO  = Hg

H2SO4 + HgO intermolecular forces

The intermolecular forces on H2SO4 and Hg2(NO3)2 are-

H2SO4 + HgO reaction enthalpy

H2SO4 + HgO change in reaction enthalpy is 6.44 kJ/mol,

Follow the below steps to calculate change in reaction enthalpy –

  • Tabulate down the reactant side of each compound on the reactant side and product side as shown below
CompoundsEnthalpy (kJ/mol)
Reaction Enthalpy of each compound in the reaction
  • Change in reaction enthalpy = Sum of enthalpies in product side – sum of enthalpies in reactant side.
  • Change in Enthalpy  =  (-707.5-285.83) – (-909.27-90.83) = +6.67 kJ/mol.

Is H2SO4 + HgO a buffer solution?

H2SO4 + HgO is not a  buffer solution because reaction is carried out in presence of strong H2SOacid.

Is H2SO4 + HgO a complete reaction?

H2SO4 + HgO is described as a complete reaction since moles of reactant are consumed completely to yield products at equilibrium.

Is H2SO4 + HgO an exothermic or endothermic reaction?

H2SO4 + HgO is an endothermic reaction because the change in enthalpy is +6.44 kJ/mol, which is positive thereby decreasing the temperature.

Is H2SO4 + HgO a redox reaction?

H2SO4 + HgO is not a redox reaction because the oxidation state of elements remains unchanged throughout the reaction.

Is H2SO4 + HgO a precipitation reaction?

H2SO4 + HgO is not a precipitate reaction. When HgSO4 is added to a solution containing tertiary compunds it will give a red or yellow precipitate.

Is H2SO4 + HgO reversible or irreversible reaction?

H2SO4 + HgO is not a reversible reaction. The reaction can only be reversed when there is a drastic change in temperature or pressure.

Is H2SO4 + HgO displacement reaction?

H2SO4 + HgO shows a  double displacement (metathesis) reaction. In this reaction, SO4 is reacted with Hg to form HgSO4, and H2 reacts with O to form H2O.


The reaction of mercuric oxide with hydrogen sulphate is a endothermic, double displacement reaction.  Mercury sulphate is commonly used as catalysts in oxymercuration – demercuration, also in the production of acetaldehyde. It is an odorless solid which forms crystalline powder or white granules.

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