15 Facts on HBr + ZnO: What, How To Balance & FAQs

ZnO is an inorganic compound soluble in acids and bases but is insoluble in water and HBr is a diatomic molecule. Let us discuss reactions about HBr+ ZnO below.

Hydrogen bromide is an inorganic and colorless gas with a pungent smell, and it is represented as HBr. Zinc oxide appears white-colored and insoluble in water and is an inorganic compound with the ZnO formula which is also known as calamine or zinc white.

This article will discuss some important facts about HBr + ZnO reaction, balanced and ionic equations, conjugate pairs, intermolecular forces, and includes types of reactions.

What is the product of HBr and ZnO

The products of HBr + ZnO are Zinc bromide (ZnBr2) and water (H2O).

HBr + ZnO = ZnBr2 + H2O

What type of reaction is HBr + ZnO

HBr + ZnO is an acid–base or neutralization reaction where HBr is acid and ZnO is base.

How to balance HBr + ZnO

HBr + ZnO reaction is balanced using the following steps.

2HBr + ZnO = ZnBr2 + H2O

  • Label each compound of reactants and products in the equation with a variable representing the unknown coefficients, such as A, B, C, and D.
  • A HBr + B ZnO = C ZnBr2 + D H2O
  • Make an equation for each element in the reaction above, where each term denotes the number of atoms on the reactant and product side.
  • H- 1A + 0B = 0C + 2D
  • Br- 1A + 0B = 2C + 0D
  • Zn – 1A + 0B =1C + 0D
  • O – 0A + 1B = 0C + 1D
  • Solve for each variable by substitution and gaussian elimination is shown below
  • 1A – 2D = 0, 1A – 2C =0, 1A- 1C =0, 1B – 1D = 0
  •  To determine the number of atoms in each element on the right and left sides to verify that all elements and electrons are balanced.
Number of moles of each element
  • Since there is an equal number of elements in the reactants and product part, so the equation is balanced.
  • Thus, the balanced equation is
  • 2HBr + ZnO = ZnBr2 + H2O

HBr + ZnO titration

Qualitative estimation of HBr can be done by titration between HBr and ZnO because, in this reaction HBr acts as a strong acid and ZnO is a weak base, so titration of this acid-base reaction is practical. For titration reaction, some important steps are outlined below.


  • A burette
  • Pipette
  • Conical flask and glass funnel
  • Clamp stand and measuring cylinder
  • Beakers


Phenolphthalein acts as an indicator in the respective titration reaction, where the titration is done in acidic media because HBr is a strong acid.


  • A standard amount of HBr is filled in the burette where HBr is used as a titrant.
  • An aqueous solution of ZnO is pipette out into the conical flask and is used as an analyte, and 2,3 drops of phenolphthalein are added.
  • Then HBr is added carefully to the conical flask and continually stir conical flask to ensure mixing.
  • The stopcock of the burette is closed at the exact point, which changes the indicator’s color. And it will be the endpoint.
  • This procedure is repeated three times to determine the constant endpoint.
  • From the final reading normality of the titrant can be calculated by the equation N1V1=N2V2

HBr+ ZnO net ionic equation

The net ionic equation for the reaction HBr + ZnO is-

2H+(aq) + ZnO(S) = Zn2+(aq) + H2O(l)

Formation of net ionic equation follows some general rules given below

  • Write the balanced molecular equation first
  • 2HBr + ZnO = ZnBr2 + H2O
  • Then write the state for each substance in the equation s,l,g or aq.
  • 2HBr(aq) + ZnO(S) = ZnBr2(aq) + H2O(l)
  • Split strong electrolytes into ions and break the electrolytes
  • 2H+ (aq)+2Br(aq)+ ZnO(s) = Zn2+(aq) +2Br(aq) +H2O(l)
  • Cancel out any spectator ions same on reactants and products side of complete ionic equation Br is the spectator ion in the above equation.
  •  Thus, the remaining substance is the net ionic equation
  • 2H+(aq) +ZnO (S)=Zn2+ + H2O(l)

HBr + ZnO conjugate pairs

In HBr + ZnO reaction conjugate pairs are

  • Bris the conjugate base and H3O+ is the conjugate acid of HBr and ZnO.
  • ZnBr2 does not have any conjugate pairs where they are polarized.

HBr and ZnO intermolecular forces

HBr + ZnO has the following intermolecular forces

  • HBr can form dipole- dipole interaction and is a polar molecule.
  • ZnO contains ionic forces.
  • ZnBr2 shows electrostatic forces.
  • H2O molecules contain intramolecular hydrogen bonding.

HBr + ZnO reaction enthalpy

HBr + ZnO reaction enthalpy is -386.8 kJ/mol.

Is HBr + ZnO a buffer solution

The HBr + ZnO reaction produces a buffer solution of ZnBr2 and H2O which maintains the changes in the pH value when acid or base is added in the solution.

Is HBR + ZNO a complete reaction

HBr + ZnO is a complete reaction because in this reaction HBr is completely reacted with ZnO and form ZnBr2 and water, so that the reaction is completely neutralized.

Is HBr+ ZnO an exothermic or endothermic reaction

HBr + ZnO is an exothermic reaction because the reaction enthalpy value is negative (-386.8 kJ/mol), that involves the release of energy in the form of heat.

Is HBr + ZnO a redox reaction

HBr + ZnO reaction is not a redox reaction because the oxidation state of each element is unchanged in the reactants and products part without any transfer of electrons during the reaction given below

2H+1Br-1 + Zn+2O-2 = Zn+2Br2 -1+ H2 +1O-2

Is HBr + ZnO a precipitation reaction

HBr + ZnO reaction is not a precipitation reaction because no precipitate is formed when HBr reacts with ZnO.

Is HBr + ZnO reversible or irreversible reaction

HBr+ ZnO is irreversible reaction because products cannot be converted into reactants, so the neutralization reaction is always irreversible.

Is HBr+ ZnO displacement reaction

HBr + ZnO reaction is double – displacement reaction because in this reaction, Br is displaced from HBr and combines with Zn to form ZnBr2 and H is displaced and combines with O to form H2O.

Screenshot 2023 01 WP
Double – displacement reaction


HBr+ZnO reaction is a double displacement and irreversible reaction where HBr is a strong acid that reacts with amphoteric oxide (ZnO) and forms ZnBr2 and water. ZnBr2 is used for metals and electrolysis.