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

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The most simple way of expressing a chemical reaction is by using chemical symbols. Let us discuss the reaction of HBr and Li2S.

Hydrogen bromide or HBr is a strong acid and lithium sulphide, Li2S is an inorganic compound. Hydrogen bromide is a colorless gas with molar mass 80.91 g/mol while lithium sulphide is a colorless solid substance with 45.95 g/mol.

Lithium sulphide has high melting and boiling point. It easily gets dissolve in water and ethanol. Its crystal structure is cubic. Li2S is mainly used for the production of lithium sulphur batteries. Let us discuss the reaction between HBr and Li2S with all details.

What is the product of HBr and Li2S?

HBr reacts with Li2S to give the products mercuric bromide and water.

HBr + Li2S ——–> LiBr + H2S

What type of reaction is HBr + Li2S?

HBr + Li2S is a double displacement reaction or metathesis. In this reaction hydrogen is replaced by lithium to form the products like lithium bromide and hydrogen sulphide.

hbr + li2s
Displacement reaction

How to balance HBr + Li2S?

To balance the reaction between HBr and Li2S, follow the below given steps:

  • Assign certain coefficients to both reactants and products,
    a HBr + b Li2S ———–> cLiBr + d H2S
  • A linear equation is made with the above reaction,
    H= a= 2d, Br =a =c, Li =2b = c, S = b=d
  • The linear equation made is, a=2d, a=c, 2b=c, b=d
  • Solve the above equation using gauss elimination method,
    a =2, b= 1, c= 2, d= 1
  • The balanced equation of HBr + Li2S is,
    2 HBr + Li2S ———–> 2LiBr + H2S

HBr + Li2S titration

HBr + Li2S titration cannot be done. Li2S is a neutral substance and HBr is a strong acid. So they can not titrate with each other.

HBr + Li2S net ionic equation

The net ionic equation of HBr and Li2S is,

2H+ + S2- ———> H2S

The ionic dissociation of HBr, Li2S and LiBr are,

2H+ + Br– ——–> HBr

2Li+ + S2- ——-> Li2S

2Li+ + 2Br– ——-> LiBr

HBr + Li2S conjugate Pairs

  • The conjugate base of HBr is Br- or bromide ion.
  • The Conjugate acid of HBr is H2Br+ or bromonium.
  • The conjugate acid of Li2S is not found because lithium sulphide is an inorganic neutral substance.

HBr and Li2S intermolecular forces

The intermolecular forces exist between HBr + Li2S is,

  • Dipole dipole interaction is acting in between hydrogen and bromine.
  • Ionic interaction is observed in lithium and sulphur.
  • In HBr, a dipole is formed in between hydrogen and electronegative bromine atom.
  • In Li2S, lithium cation and sulphide anion interacts through electrostatic force of attraction to make the bond.

HBr + Li2S reaction enthalpy

The reaction enthalpy of HBr + Li2S is 110.75 KJ/mol. The enthalpy of formation of HBr, Li2S, LiBr and H2S is -35.66, -447, -350.91 and -21 kJ/mol respectively. Hence the enthalpy is (-21+-350.91 –(-35.66 + – 447)= -110.75 KJ/mol.

Is HBr + Li2S a buffer solution

HBr + Li2S is not a buffer solution. A buffer solution is prepared by the intermixing of a weak acid or a weak base with its conjugate base or acid respectively. Here, HBr is a strong acid and Li2S is an inorganic substance. They can not be dissolved together to get a buffer solution.

Is HBr + Li2S a complete reaction?

HBr + Li2S is a complete reaction. The reaction is complete with stable products. All the reactant molecules were completely converted into corresponding products.

Is HBr + Li2S an exothermic or endothermic reaction?

HBr + Li2S reaction is an endothermic reaction. Since the enthalpy of this reaction calculated is positive it is an endothermic reaction.

Is HBr + Li2S a redox reaction?

HBr + Li2S is not a redox reaction. In a redox reaction, both oxidation and reduction happens. Here in this reaction, the oxidation state of both the reactants and products are same. So the reaction is found to be a non redox reaction.

Is HBr + Li2S a precipitation reaction?

HBr + Li2S reaction is not a precipitation reaction. It does not form any insoluble precipitate. Hydrogen sulphide formed is gas and lithium bromide is a clear white liquid.

Is HBr + Li2S reversible or irreversible reaction?

HBr + Li2S is an irreversible reaction. This reaction can not be reverted back to give the reactants as the reaction entropy rapidly increases due to the evolution of H2 gas, thereby increasing the feasibility of forward reaction.

Is HBr + Li2S a displacement reaction

HBr + Li2S is a double displacement reaction. In this reaction the anions and cations of both the reactants are exchanged each other to get the stable products like water and mercuric bromide

Conclusion

In this article, HBr and Li2S reaction is discussed. Lithium bromide and hydrogen sulphide is formed as a result of this chemical reaction. H2S is a flammable and toxic substance with rotten egg like smell.