15 Facts on HCl + Li2S What, How To Balance & FAQs

In this reaction, 1 mole of aqueous Li2S reacts with 2 moles of aqueous HCl to form 1 mole of solid H2S and 2 moles of aqueous LiCl. Let us discuss this reaction in a bit more detail.

HCl(Hydrochloric acid) is a very strong acid that completely dissociates in water. It is also known as muriatic acid, has a molar mass of 36.458 g/mol. HCl is colorless and has a pungent smell. Li2S is a deliquescent powder of yellow-white color. It has wide use in lithium-sulfur batteries.

HCl is formed by the reaction of hydrogen gas and chlorine gas and is used as a laboratory reagent. We will look into some more information about this reaction in this article.

What is the product of HCl and Li2S

HCl and Li2S react to form two products: lithium chloride and Hydrogen sulfide.

  • Li2S + HCl→ LiCl + H2S.

What type of reaction is HCl+ Li2S

The reaction of HCl and Li2S is a Double Displacement reaction as Li and H interchange changes their anionic parts to form H2S and LiCl.

How to balance HCl + Li2S

The steps involved in the reaction of HCl + Li2S to form LiCl + H2S are illustrated below:

  • The unbalanced equation is
  • Li2S + HCl→ LiCl + H2S
  • Examine the number of atoms on both sides of the chemical equation


ElementsNo of atoms on reactant sideNo of atoms on reactant side
Balancing of the reaction



  • To balance Li atoms, we must multiply Li by 2 on the right side and multiply H by 2 on the left side.
  • The balanced chemical equation is,
  • Li2S+ 2HCl→ 2LiCl + H2S
  • Inspection of the above equation shows that atoms of all elements are equal on both sides.

HCl+ Li2S titration

There are insignificant results in the titration of Li2S and HCl, as Li2S is a strong electrolyte.

HCl+ Li2S net ionic equation

  • First, the complete equation is written along with their physical states.
  • Li2S(aq) + 2HCl(aq) = H2(s) + 2LiCl(aq)
  • Then break all the soluble compounds in their particular ions.
  • 2Li+(aq) + S2-(aq) + 2H+(aq) +2Cl(aq) =H2S (s)+ 2Li+(aq) +2Cl(aq)
  • Now remove all the ions on both the product and reactant side, also known as spectator ions. Those are Li+ and Cl. The net ionic reaction is
  • S2-(aq) + 2H+(aq)= H2S(s)

HCl+Li2S conjugate pairs

In the above reaction, no conjugate pairs can be made because HCl is a strong acid with conjugated base Cl, and Li2S is a weak acid. Therefore, when a proton is added to a base, a conjugated acid is formed, and when a proton is removed from an acid, a conjugated acid is formed.

HCl and Li2S intermolecular forces

  • The two types of intermolecular forces between the HCl molecule are present precisely: dipole-dipole interaction and London dispersion force.
  • Between the Li2S molecule, an ionic bond is present. The ions are Li2+and S2-respectively.

HCl + Li2S reaction enthalpy

The enthalpy of the final reaction HCl +Li2S is −211.8 kJ mol-1.

Is HCl + Li2S a buffer solution

HCl+ Li2S will not be a buffer solution because HCl is a strong acid; but a buffer solution involves a weak acid and a salt revived from a weak base and salt of weak base.

Is HCl + Li2S a complete reaction

Hydrochloric acid with lithium sulfide is a complete reaction as two reactants are combined to form two complete products, and double displacement takes place.

Is HCl + LI2S an exothermic or endothermic reaction

The reaction between HCl +Li2S is exothermic as it releases a large amount of heat because the formation of ionic compounds is always an exothermic reaction.

Is HCl + Li2S a redox reaction

HCl + Li2S is not a redox reaction, and the reason is that there is no change in the oxidation numbers on both sides (reactant and product)

Is HCl + Li2S a precipitation reaction

HCL + Li2S is not a precipitation reaction as the products formed, LiCl and H2S, are both soluble in water.

Is HCl + Li2S reversible or irreversible reaction

HCl + Li2S is irreversible as this reaction moves only in one direction.

Is HCl+ Li2S displacement reaction

HCl + Li2S is not a displacement reaction because both Li and H interchange their anionic parts, making it a double displacement reaction.


HCl + Li2S is a strong acid reaction with the salt of a weak acid, and the product formed is a weak acid. It belongs to a group of acid-base reactions and has a binary nature. The products formed, H2S, is colorless and has a characterstic odor of rotten eggs whereas LiCl is an hygroscopic compound with small size ions.

Deepali Arora

Hi....I am Deepali Arora and presently working as a Subject Matter Expert in Chemistry. I have henceforth completed my graduation and post-graduation in life sciences and chemistry respectively. I am highly inquisitive as far as learning and experimental aspects are concerned. I am looking forward to strengthening my career in the same field. I am good at troubleshooting and have a good critical thinking and analytical approach. Connect me via LinkedIn: https://www.linkedin.com/in/deepali-arora-571707202

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