13 Facts on HBr + Cl2: What, How To Balance & FAQs

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Hydrogen bromide (HBr) and chlorine (Cl2) are inorganic compounds that exist as gas at room temperature. Let us learn more about their reaction in this article.

HBr is a colorless gas that finds application as a catalyst and reducing agent in organic reactions. Cl2 is a pungent, yellow-green gas used as a bleaching agent and water disinfectant due to its strong oxidizing nature. Both these gases, HBr and Cl2, are denser gases made up of halogens.

In this article, we will gain knowledge about the HBr + Cl2 reactions and some of their characteristics like the product, type of reaction, reaction enthalpy, reversibility, etc.

What is the product of HBr and Cl2?

Hydrochloride (HCl) and bromine (Br2) are the products of HBr + Cl2.

2HBr + Cl2 –>2HCl + Br2

What type of reaction is HBr + Cl2?

HBr + Cl2 is a single displacement reaction. In this reaction, Cl displaces Br.

How to balance HBr + Cl2?

To balance HBr + Cl2 reaction,

First, write the chemical equation such that the reactants are on the left side and the products are on the right

HBr + Cl2 –> HCl + Br2

  • To get a balanced reaction, the number of atoms of an element must be the same on both sides.
  • When we calculate, the number of bromines on the left is 1, and the number of bromines on the right is 2; similarly, the number of chlorines on the right is 1, and the number of chlorines on the left is 2.
  • To make it balanced, add 2 as a stoichiometric ratio to HBr on the left and to HCl on the right.
  • Now the equation becomes as,

2HBr + Cl2 –> 2HCl + Br2

If we count the number of atoms of each element on both sides, they come to be equal. The equation is now balanced.

HBr + Cl2 titration

HBr and Cl2 can be titrated in the following manner to estimate the strength of the HBr solution.

Apparatus

Burette, burette holder, conical flask, pipette, glass rod, measuring cylinder, wash bottle

Indicator

DPD (N,N-diethyl-p-phenylenediamine) is the indicator used for this experiment. Cl2 in water gives rise to free chlorines. This indicator detects that and shows a magenta color. When the chlorine is used up, it becomes colorless. That is our endpoint.

Procedure

  • Take a solution of Cl2 passed in water with a known strength in a conical flask.
  • Add a few drops of DPD into the conical flask. The solution will become magenta. If the concentration of chlorine is too much, the color might be faint. But along the experiment, the color will become darker and fall sharply to colorless when chlorine concentration comes to zero.
  • Fill the burette with HBr solution.
  • Open the burette knob such that the solution falls dropwise into the conical flask.
  • Keep swirling and stirring the conical flask and close the knob once the solution becomes colorless.
  • Note the volume readings and repeat the experiment till 3 consistent readings are obtained. Take the average of the volume readings and substitute in the following equation to get the strength.

StrengthCl2 x VolumeCl2 = StrengthHBr x VolumeHBr

Remember to perform this experiment in a safe area with proper ventilation.

HBr + Cl2 net ionic equation

2H+(aq) + 2Br–(aq) + Cl2(g) –> 2H+(aq) + 2Cl–(aq) + Br2(aq)

The net ionic equation can be obtained by the following method:

  • Write the balanced chemical equation.
  • Write the ionic form of each compound in an aqueous solution.
  • HBr will split into H+, and Br– and Cl2 will not dissociate into ionic form. HCl will be in H+ and Cl– form and Br2 will remain intact.
  • Now write the state of existence for each molecule.
  • H+ and Br– will be in an aqueous form, and Cl2 will be a gas in the beginning. H+ and Cl– will be in the aqueous form, and Br2 will also be in the aqueous form before it escapes as gas.
  • When all these steps are followed, the net ionic equation is obtained.

HBr and Cl2 intermolecular forces?

HBr and Cl2 have the following intermolecular forces

  • In HBr, the intermolecular forces are dipole-dipole forces.
  • The intermolecular forces in Cl2 are dispersion forces.

HBr + Cl2 reaction enthalpy?

The reaction enthalpy of HBr + Cl2 is -230.953 kJ.

This can be calculated by subtracting the enthalpy of formation of products from the enthalpy of formation of reactants.

  • Enthalpy of formation of 2HBr = 2 mol x -36.23 kJ/mol = -72.46 kJ
  • Enthalpy of formation of Cl2 = 0 kJ/mol
  • Enthalpy of formation of 2HCl = 2 mol x -167.16 kJ/mol = -334.32 kJ
  • Enthalpy of formation of Br2 = 1 mol x 30.907 kJ/mol = 30.907 kJ
  • Enthalpy of reaction = 30.907 kJ + (-334.32 kJ) – 0 kJ/mol – (-72.46 kJ) = -230.953 kJ
  • ΔrH˚ = -230.953 kJ

Is HBr + Cl2 a complete reaction?

HBr + Cl2 is a complete reaction, as the limiting agent in these reactants will be used up as the products are removed.

Is HBr + Cl2 an exothermic or endothermic reaction?

HBr + Cl2 is an exothermic reaction, as the reaction enthalpy is negative.

ΔrH˚ = -230.953 kJ

Is HBr + Cl2 a redox reaction?

HBr + Cl2 is a redox reaction. The oxidation state of Br increases to 0 from -1, and the oxidation state of Cl reduces to -1 from 0. Since both oxidation and reduction occur in this reaction, this is called a redox reaction.

Is HBr + Cl2 a precipitation reaction?

HBr + Cl2 is not a precipitation reaction as the products HCl and Br2 are not even solids.

Is HBr + Cl2 reversible or irreversible reaction?

HBr + Cl2 is a reversible reaction. In a closed system, the reaction is in equilibrium.

Is HBr + Cl2 displacement reaction?

HBr + Cl2 is a single displacement reaction. Cl displaces Br in HBr to form HCl and Br2.

Screenshot 2022 12 11 195605
Image representing single displacement reaction in HBr + Cl2

Conclusion

In this article, we have learned some of the facts related to the HBr + Cl2 reaction. This is one of the important reactions in chemistry, and the products of this reaction, HCl and Br2, have multiple industrial applications.