15 Facts on HCl + Mg2Si: What, How to Balance & FAQs

Hydrochloric acid is the strong acid and magnesium silicide is a colorless compound. Let us know about the HCl + Mg₂Si reaction.

Hydrochloric acid is an aqueous solution of hydrogen chloride. It is also known as muriatic acid, which is colorless solvent with pungent odour. Magnesium silicide is a crystalline inorganic compound which is used in semiconductor with N-type conductivity.

In this article we will discuss about the reaction between Hydrochloric acid and Magnesium silicide, balancing of reaction and redox mechanism of the reaction etc.

What is the product of HCl & Mg₂Si

Silane and Magnesium chloride is formed when Hydrochloric acid reacts with Magnesium silicide.

4HCl + Mg₂Si = SiH₄ + 2MgCl₂

What type of reaction are HCl+Mg₂Si

HCl + Mg₂Si is a redox (reduction-oxidation) reaction. In which reaction both oxidation and reduction occur simultaneously, HCl acts as a reducing agent and Mg₂Si acts as an oxidising agent.

How to balance HCl+Mg₂Si

The reaction is balanced using the following steps

HCl + Mg₂Si = SiH₄ + MgCl₂

• The number of atoms present on both sides is counted, which should be the same.

Reactant Side	Product Side
1-Hydrogen atom	4-Hydrogen atom
1-Chlorine atom	2-Chlorine atom
2-Magnesium atom	1-Magnesium atom
1-Silicon atom	1-Silicon atom

• The number of Hydrogen atoms on both the sides of the reaction is balanced by adding coefficient 4 to the Hydrochloric acid at reactant side.

• 4HCl + Mg₂Si = SiH₄ + MgCl₂

• To balance the Magnesium atoms add coefficient 2 to the product side.

• 4HCl + Mg₂Si = SiH₄ + 2MgCl₂

• Thus the balanced chemical reaction is:

• 4HCl + Mg₂Si = SiH₄ + 2MgCl₂

HCl + Mg₂Si Titration

HCl can not be titrated with Mg₂Si because Magnesium silicide is not a base.

HCl + Mg₂Si net ionic equation

The net ionic equation for the reaction HCl + Mg₂Si is-

4H⁺(aq) + Mg₂Si (s) = SiH₄ + 2Mg²⁺ (aq)

The net ionic equation is derived using the following steps.

• The reaction written in the form of ionic compounds with its charge are as follows:

• 4H⁺(aq) + 4Cl^– (aq) + Mg₂Si (s) = SiH₄ + 2Mg²⁺ (aq) + 4Cl^– (aq)

• The net ionic equation is as follows by removing the spectator ions (ions those are same on reactant & product sides)

• 4H⁺(aq) + Mg₂Si (s) = SiH₄ + 2Mg²⁺ (aq)

HCl + Mg₂Si conjugate pairs

• Conjugate base of HCl is Cl^–.
• Conjugate base Mg₂Si is Si^4-

HCl + Mg₂Si Intermolecular forces

• Hydrochloric acid has dipole-dipole & London dispersion forces of attraction and shows ionic interactions in aqueous media.
• Magnesium silicide is covalently bonded to each other.

HCl + Mg₂Si reaction enthalpy

The reaction enthalpy of HCl + Mg₂Si is 858.53 KJ/mol

Compound	Moles	Enthalpy of formation, ΔH0f (KJ/mol)
HCl	4	-92.3
Mg2Si	1	-21.20
SiH4	1	34.31
MgCl2	2	-641.62

• The standard enthalpy of a reaction is calculated using the formula:

• ΔH⁰_{f (reaction)} = ΣΔH⁰_{f (product)} – ΣΔH⁰_{f (reactants)}

• Thus, enthalpy change = [4*(-92.3) + 1(-21.20)] – [1*(34.31) + 2*(-641.62)] KJ/mol
• = 858.53 KJ/mol

 Is HCl + Mg₂Si a buffer solution

HCl + Mg₂Si will not form a buffer solution due to the presence of strong hydrochloric acid.

Is HCl + Mg₂Si a complete reaction

HCl + Mg₂Si is a complete reaction because it produces stable compounds Silane & Magnesium chloride.

Is HCl + Mg₂Si an exothermic or endothermic reaction

HCl + Mg₂Si is an exothermic reaction because it releases heat to the surrounding while producing the product.

Is HCl + Mg₂Si a redox reaction

HCl + Mg₂Si is a redox reaction due to the change in oxidation state of Silicon ion in reactant and product side.

4H⁺ + 4Cl^– + Mg₂²⁺ + Si^4- = Si⁴⁺ + H^–₄ + 2Mg²⁺ + 2Cl^–₂

Is HCl + Mg₂Si a precipitation reaction

HCl + Mg₂Si is not a precipitation reaction because no precipitate forms during the reaction.

Is HCl + Mg₂Si a reversible or irreversible reaction

HCl + Mg₂Si is an irreversible reaction, because the products formed do not react to give back reactants under the same condition.

Is HCl + Mg₂Si a displacement reaction

HCl + Mg₂Si is a double displacement reaction. Because here, chloride ion is displaced from HCl molecule & silicon ions from Mg₂Si molecule to produce Silane & Magnesium chloride.

4H⁺ + 4Cl^– + Mg₂ + Si = SiH₄ + 2Mg²⁺ + 4Cl^–

Conclusion

HCl + Mg₂Si produced Silane & Magnesium Chloride which is used for commercial as well as laboratory purpose. Silane is a precursor of elemental Silicon also effective water repellents for minerals surfaces. Magnesium chloride is the important precursor of magnesium metal.