13 Facts on HBr + Fe: What, How To Balance & FAQs

Hydrogen Bromide is a strong acid, and Ferrous, also called Iron, is a group VIIb metal. Let us study these elements.

HBr is covalently bonded between Hydrogen and bromine, and HBr is a colorless gas with a smell. The combustion of Bromine and Hydrogen manufactures HBr. Ferrous is also called Iron. Fe is a transition metal found in the earth’s crust. Iron readily reacts with air and forms ferric oxide called ion rust.

In this article, we will discuss a few properties based on the reaction HBr + Fe, like the reaction types, the product formed after the reaction, buffer solution, conjugate pairs etc.

What is the product of HBr and Fe?

The product of the HBr and Fe reaction is Ferrous bromide and Tritium, which is called H2 gas.

HBr+ Fe———>FeBr2+H2

What type of reaction is HBr + Fe?

HBr+ Fe reaction is a single displacement reaction and redox reaction.

How to balance HBr + Fe

The general equation of HBr+ Fe reaction is,

HBr+ Fe———>FeBr2+H2

  • Let’s Calculate the number of atoms of each element involved in the reactant and product side.
  • HBr+ Fe———>FeBr2+H2
No. of elements in ReactantNo. of elements in a Product
Elements description
  • Considering the above table, the number of Fe in reactant and product are the same. Still, the number of H and Br are not equal in reactant and product, so it is considered an unbalanced equation.
No. of elements in ReactantNo. of elements in Product
Elements description
  • The number of atoms of each element on the reactant side equals that on the product side.
  • Thus the reaction is self-balanced, and the overall balanced reaction is given by 
  • 2HBr+ Fe———>FeBr2+H2

HBr + Fe titration

We cannot titrate HBr and Fe because ferrous is metal. We cannot titrate a metal with acid. For metal titration, we need a very strong metal complex, and Fe doesn’t have a strong complex to titrate with HBr; the reaction between HBr and is highly exothermic, so it isn’t easy to handle while titration.

HBr + Fe net ionic equation

The net ionic equation for HBr and Fe is as follows,

2H+(aq) + 2Br(aq) + Fe(s) = Fe2+(aq) + Br-(aq) + H2(g)

HBr + Fe conjugate pairs

HBr + Fe reaction has the following conjugate pairs,

  • During the course of the reaction, HBr loses a proton to form Br.
  • Here HBr and Br act as conjugate acid-base pairs where Br is the conjugate base of HBr.

HBr and Fe intermolecular forces

HBr + Fe reaction has the following intermolecular forces,

  • Because of HBr polarity, it has dipole-dipole forces. There are also dispersion forces between HBr molecules.
  • Fe is a neutral molecule; hence it has only London dispersion force as the dominant intermolecular force.

HBr+ Fe reaction enthalpy

The change in enthalpy formation in 2HBr+ Fe=FeBr2+H2 is -320.67008. Hence the reaction enthalpy is negative.

  • The enthalpy of reactant Fe(s) is 0
  • The enthalpy of reactant HBr(aq) is -36.44284
  • The enthalpy of product FeBr2(aq) is -249.7848
  • The enthalpy of product H2 (g) is 0
  • [(FeBr2+H2) – (2HBr+Fe)] =[(-247.7848)+(0)] – [(2X-36.44264)+(0)] =[-247.7848] – [-72.88528] = -320.67008.

Is HBr + Fe a buffer solution

HBr + Fe reaction is not a buffer solution since HBr is a very strong mineral acid, it completely dissociates to H+ and Br in an aqueous medium.

Is HBr + Fe an exothermic or endothermic reaction

HBr and Fe is exothermic as during the reaction, the amount of energy released is greater than the amount of energy absorbed with reaction enthalpy is negative.

Is HBr + Fe a redox reaction

HBr +Fe reaction is a redox (oxidation-reduction reaction) reaction since the Fe is oxidized by HBr and forms a ferrous ion, and HBr consumes Fe released electrons.

Is HBr + Fe a precipitation reaction

HBr + Fe reaction is a precipitation reaction because HBr loses the Hydrogen and acts as a cation Br and it reacts with metal cation Fe2+.

Is HBr + Fe reversible or irreversible reaction

HBr + Fe reaction is the irreversible reaction because of redox reactions spontaneous reactions. They transfer electrons in only one way.

Is HBr+ Fe displacement reaction?

HBr+ Fe is a single displacement reaction because the single anion and cation switch places to form FeBr2 and H2.


The reaction of HBr and Fe is exothermic and takes place at room temperature. Although HBr is an important reagent used in preparing various inorganic and organic bromides. As Fe is a very useful metal in human life and Fe is used for some synthetic reactions like reduction.