15 Facts on HCl + Al2S3: What, How To Balance & FAQs

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Aluminium sulphide is also referred to with the chemical formula Al2S3. Let us look at some facts regarding Al2S3 and HCl reactions.

Hydrogen chloride is a colourless to faintly yellow gas with a pungent odour. Strong acids like HCl can dissociate into ions and react with a variety of metals and other compounds. The chemical compound known as aluminium sulphide(Al2S3) has a molar mass of 150.158 g/mol and is a grey solid.

Al2S3 is created by heating aluminium directly in the presence of sulphur. Let us study the facts based on the HCl + Al2S3 reaction will be covered below.

What is the product of HCl and Al2S3?

When Hydrogen Chloride(HCl) is reacted with Aluminium sulphide(Al2S3), the products obtained are Aluminium chloride(AlCl3) and hydrogen sulphide(H2S) gas. An Aluminum Chloride product is formed that is soluble in water. Hydrogen Sulfide gas is released during the reaction.

HCl + Al2S3 → AlCl3 + H2S

What type of reaction is HCl + Al2S3?

HCl + Al2S3 is the Double displacement reaction because ions replaced each other. 

HCl(s) + Al2S3(aq) → AlCl3(aq) + H2S(g)

How to balance HCl + Al2S3?

HCl + Al2S3 can be balanced easily by following these steps:

  • Step 1: To identify reactants and products, count their atoms:
  • Count each type of atom on both the reactant and product sides first. On the reactant side, there are the atoms 1H, 1Cl, 2Al, and 3S. On the product side, there are atoms of 1Al, 2H, 1S, and 3Cl.
  • Unbalanced equation: HCl + Al2S3 = AlCl3 + H2S
  • Step 2: Balancing the atomic composition of reactants and products:
  • The atoms or molecules in HCl-Al2S3 are balanced or organised by multiplying 6 by HCl, 2 by AlCl3, and 3 by H2S.
  • 6HCl + Al2S3 = 2AlCl3 + 3H2S
  • Step 3: Calculate the coefficient: Gauss elimination is used to calculate all of the coefficients and variables. The result is a 6:1::2:3 coefficient.
  • Step 4: Balanced chemical equation:
  • 6HCl + Al2S3 → 2AlCl3 + 3H2S

HCl + Al2S3 titration

A titration between Al2S3 and HCl can be used to measure the amount of Al. The reaction should be carried out extremely carefully because the result is a precipitate(AlCl3).

Apparatus Required

White paper, Volumetric and Erlenmeyer flasks, Burette(50 mL), Beaker and a Burette stand are all required.

Indicator

The phenolphthalein indicator works well to perform the titration between HCl and Al2S3 since it is a type of acid-base reaction. It becomes colourless in acidic media while changing to a pale pink colour in basic media. 

Procedure

  • The device must be correctly cleaned and rinsed with the appropriate chemicals, using a minimum amount of chemicals.
  • The Al2S3 solution is taken in the Erlenmeyer flask while standardised HCl is put into the Burette.
  • The phenolphthalein indicator is then added to the reaction mixture and thoroughly mixed.
  • When titrating, release one drop of HCl from the burette at a time until a perceptible colour change occurs.
  • When a perceptible colour shift appears, we can say the reaction’s endpoint has been reached.
  • The procedure should be used three times to calculate accurate readings.
  • The necessary amount can be calculated using the equation N1V1=N2V2.

HCl + Al2S3 net ionic equation

HCl + Al2S3 reaction has the following net ionic equation,

6H+(aq) + 6Cl–(aq) + 3S2-(aq)+ 2Al3+(aq) → Al3+(aq) + 3 Cl–(aq) + H2S(g)

HCl + Al2S3 conjugate pairs

HCl + Al2S3 reaction produced the following conjugate pairs:

  • The conjugate base pair(Cl–) and the conjugate acid pair(H+ and S2-).
  • Al2S3 also serves as the acid.
  • HCl is the conjugate acid.

HCl and Al2S3 intermolecular forces

HCl + Al2S3 reaction has the following intermolecular force,

  • Cl is more electronegative than H and readily takes electrons from hydrogen in the HCl molecule, which is an example of a dipole-dipole and London dispersion interaction.
  • Al3+ cation and S2- anion of the sulphide interact ionically to produce intermolecular interactions in Al2S3.

HCl + Al2S3 reaction enthalpy

HCl + Al2S3 reaction has a typical reaction enthalpy of +2678.6kJ/mol,

  • ΔH⁰f(reaction) = ΣΔH⁰f(products) – ΣΔH⁰f(reactants)= -ve
  • 6HCl(s) + Al2S3(aq) → 2AlCl3(aq) + 3H2S(g) 
  • Enthalpy change = [3*(-20.6) + 2*(-706.25)] – [6*(-167.15) + 1*(-1675.7)] =+2678.6 kJ/mol.

Is HCl + Al2S3 a buffer solution?

The HCl + Al2S3 reaction is not a buffer solution, Al2S3 is in a solid state and does not entirely dissociate into ions since HCl is a powerful acid that does so. Therefore, the buffer’s creation is prevented.

Is HCl + Al2S3 a complete reaction?

The HCl + Al2S3 reaction is the complete reaction due to the following reason,

  • AlCl3 + H2S is the product of the reaction which is stable.
  • AlCl3 is a stable salt that does not dissolve in water and is stable in the free state.
  • H2S is a gas released during the reaction. 

Is HCl + Al2S3 an exothermic or endothermic reaction?

The HCl + Al2S3 reaction is endothermic because the value of standard enthalpy of formation is having a positive value.

Is HCl + Al2S3 a redox reaction?

The HCl + Al2S3 reaction is not a redox reaction, because the elements remained in their original oxidation states throughout the process. Al is in the +3 state, Cl is in the -1 state, H is in +1 and S is in the -2 state.

hcl + al2s3
The stable form of Reaction

Is HCl + Al2S3 a precipitation reaction?

The HCl + Al2S3 reaction is a precipitation reaction. Because the result of HCl + Al2S3 is made up of AlCl3 + 3H2S, which are insoluble in water. AlCl3 is a precipitate that is white and sinks to the bottom of the container. AlCl3 is insoluble in water.

Is HCl + Al2S3 reversible or irreversible reaction?

The HCl + Al2S3 reaction is an irreversible reaction, due to the solid, insoluble byproducts of the reaction. This product does not reverse the conversion to the solution.

Is HCl + Al2S3 displacement reaction?

HCl + Al2S3 is a double displacement reaction. Because metal and acids can only react in displacement reactions when the acid is especially powerful and concentrated. The substance is moisture sensitive and hydrolyses into hydrated aluminium oxides/hydroxides.

Conclusion

HCl + Al2S3 have finished their reaction, through a double displacement reaction. It results in the production of aluminium chloride, a material that is insoluble in water. It is impossible to stop this endothermic reaction and can produce a range of interesting chemical reactions.