15 Facts on HCl + F2: With Several Elements Reaction

Hydrochloric acid and Fluorine both contain halogens of the periodic table. Let us look at how their reaction occurs.

HCl can exist in both liquid and gaseous forms.Fluorine exists as a light yellow gas but can be cooled down to a yellowish liquid at -188ºC.Fluorine is the most electronegative out of all elements, for which it is extremely reactive to displacement reactions.Reaction of HCl and F2 is performed at ambient temperature.

Since Fluorine is highly electronegative, let us see how the reaction with HCl pans out.

What is the product of HCl and F2?

HCl and F2 react to form Hydrogen Fluoride and Chlorine gas respectively. In an aqueous medium, hydrofluoric acid is generated. The reaction equation is:

  • 2HCl + F2 = 2HF + Cl2

What type of reaction is HCl + F2?

The reaction of HCl with F2 is a single displacement reaction as Chlorine gets displaced by Fluorine in the product.

How to balance HCl and F2?

Following are the steps to equate the above reaction scheme:

  • HCl + F2 = HF + Cl2
  • As both sides should be equal in atoms, multiply HF with 2 to equate the fluorine atoms.
  • HCl + F2 = 2HF + Cl2
  • Multiply HCl with 2 as the product side has two hydrogen atoms.
  • 2HCl + F2 = 2HF + Cl2

HCl + F2 Titration

The titration of HCl with F2 will yield no significant results. However, to titrate fluorine content, the titration of sodium fluoride in presence of fluorine is possible where HCl maintains the pH levels.  

HCl + F2 Net Ionic Equation

The net ionic equation of HCl + F2 stands as:

  • H+ Cl–  +  F2 =  H+ F  +  Cl2

HCl + F2 Conjugate Pairs

Conjugate acid-base pairs refer those pair of compounds where the chemical difference between them is just one proton. For instance,

  • Conjugate base of HCl= Cl
  • Conjugate base of HF= F

HCl and F2 Intermolecular Forces

HCl shows ionic interactions in aqueous medium. Fluorine molecule is capable of forming strong hydrogen bonds due to its high electronegativity. Since F2 is non-polar, the Van der Waals’ forces are very weak, due to which it exists more as a gas.

ElementVan der Waals’ Radius(pm)
Table showing Van der Waal Radii
F2a ch
Fluorine bonding

HCl + F2 Reaction Enthalpy

The enthalpy information of HCl + F2 is as follows:

  • Bond Enthalpy of F2 = +158 kJ/mol
  • Bond Enthalpy of HCl = +428 kJ/mol
  • Bond Enthalpy of HF = +569 kJ/mol
  • Bond Enthalpy of Cl2 = +239 kJ/mol
  • Reaction Enthalpy of above reaction= -363 kJ/mol

Is HCl + F2 a Buffer Solution?

HCl + F2 combination will not yield a strong buffer solution as it contains a strong acid like hydrochloric acid.

Is HCl + F2 a Complete Reaction?

The HCl + F2 reaction is complete as complete products are formed at the end once equilibrium is reached.

Is HCl + F2 an Exothermic Reaction?

The resultant HCl + F2 reaction is exothermic in nature as the reaction enthalpy is negative, thereby, increasing the temperature of the system.

Is HCl + F2 a Redox Reaction?

The reaction of HCl and F2 is an actual redox reaction as:

  • Chlorine gets oxidised as the oxidation state changes from -1 to 0(elemental).
  • Fluorine gets reduced as the oxidation state changes from 0(elemental) to -1.
HFCl2 ch
Redox Scheme of the Reaction

Is HCl + F2 a Precipitation Reaction?

HCl + F2 is not a precipitation reaction as the product does not precipitate in the system.

Is HCl + F2 a Reversible Reaction?

HCl + F2 is not reversible in nature as complete products are formed which cannot revert unless there is a change in temperature and pressure or other conditions.

Is HCl + F2 a Double Displacement Reaction?

The reaction of Hydrochloric acid with Fluorine is not a double displacement reaction. It is a single displacement reaction.


The reaction of HCl with F2 forms colourless Hydrofluoric acid, which has diverse applications in organofluorine chemistry. Yellowish Chlorine gas is also observed. Fluorine acts as a strong oxidising agent in the reaction which serves as a good displacement reaction.