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

Copper oxide or cupric oxide, Cu(II)O, is a black solid soluble in H2SO4. Let us know more about the chemical reaction between CuO and H2SO4.

CuO is a basic metal oxide while H2SO4 is a corrosive strong acid. CuO is a transition metal oxide and hence soluble in dilute acids, like dilute sulphuric acid.

In this article let us discuss about the type of this reaction, conjugate pairs, balancing method and enthalpy change.

What is the product of H2SO4 and CuO?

Copper sulphate is the major product obtained along with water when aqueous H2SO4 is added to solid CuO.

CuO(s)+ H2SO4 (aq) —-> CuSO4 (aq) + H2O (l)

What type of reaction is H2SO4 + CuO?

The reaction between copper (II) oxide and sulphuric acid is an acid-base neutralization reaction, as H2SO4 is an acid and CuO is a base.

How to balance H2SO4 + CuO?

The equation between H2SO4 + CuO is balanced using the following steps.

  • The unbalanced equation of the reaction is –
  • CuO (s) + H2SO4 (aq) →  CuSO4 (aq) + H2O (aq)
  • Mole numbers of the respective species is determined on both the reactant and product sides.
ElementsReactant side (LHS)Product side (RHS)
Number of moles of each species
  • We find that the mole numbers of each element in the reactant and product side are equal. Hence the reaction is self-balanced.
  • CuO (s) + H2SO4 (aq) → CuSO4 (aq) + H2O (aq)

H2SO4 + CuO titration

Iodometric titration is used to determine the qualitative analysis of Cu2+ in any sample solution, using the following process.


250 ml conical flask, glass stopper, 20 ml pipette, burette, and measuring jar.


Starch is used as the indicator in the iodometric titration of Cu2+.


  • Pipette out 20 ml of copper sulphate solution (obtained in H2SO4 + CuO reaction) containing copper (II) into a conical flask fitted with a glass stopper.
  • Add a few drops of ammonium hydroxide till the solution turns dark blue. Then add a few drops of acetic acid till the solution loses its dark blue color.
  • Now add 5 ml of KI solution and titrate against 0.1M sodium thiosulphate taken in the burette.
  • When the solution turns light brown, add 5 ml of starch indicator and continue the titration.
  • The endpoint is the disappearance of the violet-blue color.
  • 2Cu2+ + 2S2O32- + 2I → 2CuI(s) + S4O62-
  • Therefore, moles of Cu2+ = moles of S2O32-
  • The amount of Cu2+ is calculated using the formula, VCu2+ SCu2+ = VS2O32- SS2O32-

H2SO4 + CuO net ionic equation

The net ionic equation of H2SO4 + CuO is

2H+ (aq)+ CuO(s) =  Cu2+(aq) + H2O(l)

To derive the net ionic equation of a chemical reaction following steps are used.

  • Write the ionic form of each of the substances along with the state in which they exist. Cupric oxide is an insoluble solid and so does not dissociate into ions. The complete ionic equation is –
  • 2H+ (aq) + SO42-  (aq) + CuO (s) =  Cu2+(aq) + SO42- (aq) + H2O (l)
  • Cancel the spectator ions (SO42-), which appear on both sides of the equation, to arrive at the net ionic equation.
  • 2H+ (aq) + CuO(s)  =  Cu2+(aq) + H2O(l)

H2SO4 + CuO conjugate pairs

  • The conjugate pair of H2SO4 is HSO4
  • The conjugate pair of CuO is HCuO+

H2SO4 + CuO intermolecular forces

  • Electrostatic force of attraction (Columbic force) is the intermolecular force that acts in CuO, between the cupric ion (Cu2+) and oxide ion (O2-), as CuO is an ionic metal oxide.
  • Dipole-dipole, hydrogen bonding, and Van der Waals dispersion force are the forces acting in H2SO4, as it is a covalent and polar molecule.

H2SO4 + CuO reaction enthalpy

 H2SO4 + CuO reaction enthalpy is  -85.9 KJ/mole, and the negative sign indicates that heat is liberated during this reaction.

Is H2SO4 + CuO a buffer solution?

H2SO4 + CuO is not a buffer solution because the reaction mixture contains a strong acid and a weak base.

Is H2SO4 + CuO a complete reaction?

H2SO4 + CuO is a complete reaction, as copper oxide completely dissolves in warm dilute sulphuric acid to form a blue-colored copper sulphate solution.

Is H2SO4 + CuO an exothermic reaction?

The reaction between H2SO4 and CuO is highly exothermic, as the change in Gibb’s free energy and enthalpy of the reaction is negative.

Is H2SO4 + CuO a redox reaction?

H2SO4 + CuO is not a redox reaction, as the oxidation number of each element in the reaction remains unchanged.

Is H2SO4 + CuO a precipitation reaction?

The reaction H2SO4 + CuO is not a precipitation reaction as the product formed is a blue color solution of copper sulphate which on evaporation yields CuSO4 crystals.

Is H2SO4 + CuO irreversible reaction?

H2SO4 + CuO is an irreversible reaction as the new substance CuSO4 formed is blue in color and has different chemical properties. This implies that increasing the temperature will shift the reaction equilibrium in the forward direction or toward product formation.

Is H2SO4 + CuO a displacement reaction?

H2SO4 + CuO is a double displacement reaction, as the more reactive hydrogen displaces copper from copper oxide.

Double displacement reaction


The reaction between water-insoluble cupric oxide, Cu(II)O and dilute sulphuric acid results in the formation of a soluble salt, CuSO4. It is blue in color due to the dissociation of copper and sulphate ions in water.

Scroll to Top