15 Facts on HCl + Mg(OH)2 :What, How to Balance & FAQs

Hydrochloric acid, a potent inorganic acid, is used in numerous industrial processes. Mg(OH)2 is an inorganic compound. Let us discuss how HCl reacts with Mg(OH)2.

HCl is a potent acid with a molar mass of 36.458 g/mol. It is an aqueous solution of hydrogen chloride. Mg(OH)2 is a strong base with a molar mass of 58.3197 g/mol. It is found in nature as the mineral brucite. White solid, barely soluble in water.

Let us examine the interaction of HCl with Mg(OH)2 with the aid of this article.

What is the product of HCl + Mg(OH)2

The products of the reactions HCl and Mg(OH)2 are MgCl2 and H2O.

Mg(OH)2 + HCl→MgCl2 + H2O

What type of reaction is HCl + Mg(OH)2

The HCl +Mg(OH)2 is a neutralization reaction, known as a double displacement reaction. Mg(OH)2, a base, has been added to HCl, an acid, and this is neutralization.

How to balance HCl and Mg(OH)2

  • The unbalanced equation is as follows: Mg(OH)2 + HCl→MgCl2 + H2O
  • For a chemical equation to be balanced, there should be an equal number of atoms on both sides.
  • Reactant side: Mg=1, O=2, H=3, Cl=1
  • Product side: Mg=1, O=1, H=2, Cl=2
  • To balance the O atom, multiply 2 by H2O; on the product side, O = 2 and H = 4.
  • In order to balance the Cl atom, we will multiply 2 with HCl, Cl=2, and H=4 on the reactant side.
  • Mg(OH)2 + 2HCl →MgCl2 + 2H2O , balanced chemical equation.

HCl + Mg(OH)2 titration

Aim:

To determine the unknown concentration of a solution of Mg(OH)2 by titration against a standard solution of 0.1M HCl.

Apparatus required

  • Burette
  • Pipette
  • Conical flask
  • Burette stand

Indicator

Phenolphthalein is used as an acid-base indicator.

Procedure:        

  • Up to the final marked point, fill the burette with 0.1 M HCl.
  • Using a pipette, add 25mL of Mg(OH)2 to the conical flask.
  • Add 2 to 3 drops of phenolphthalein indicator to the conical flask. Placing the conical flask beneath the burette, allowing the HCl solution to drip into the flask, and repeating this procedure three times.
  • We note the two parallel readings and enter the value into the formula to determine the Mg(OH)2 concentration.
  • The endpoint is reached when the solution becomes colorless.

HCl + Mg(OH)2 Net ionic equation

The net ionic equation is:

Mg(OH)2(s) + 2H+(aq)→ Mg2+(aq) + 2H2O(l)

  • The balanced chemical equation should be written first:

                Mg(OH)2 + 2HCl→MgCl2 + 2H2O

  • For each substance, indicate the state (s, l, g or aq).

Mg(OH)2(s) + 2HCl(aq)→MgCl2(aq) + 2H2O(l)

  • Break the strong electrolyte into ions.

Mg(OH)2 + 2H+ + 2Cl→ Mg2+ + 2Cl+ 2H2O 

  • Remove the spectator ions from the entire ionic equation on both sides.

HCl + Mg(OH)2 Conjugate pairs

The reactions of HCl and Mg(OH)2 do not form conjugate acid-base pairs because the anion and cation, which are conjugates of strong acids and bases, are both weak.

HCl and Mg(OH)2 intermolecular forces

  • There are two different intermolecular forces between the HCl molecules: the London dispersion force and the dipole-dipole interaction.
  • An ionic bond exists between the Mg(OH)2 molecule; the ions are two (OH)-1 ions and the Mg2+ ion, respectively.

HCl and Mg(OH)2 Reaction enthalpy

The reaction enthalpy for HCl and Mg(OH)2 is zero as it forms a neutralization reaction.

Is HCl and Mg(OH)2 a Buffer solution

The mixture of HCl and Mg(OH)2 is not a buffer solution.

Is HCl and Mg(OH)2 a complete reaction

The reaction of HCl and Mg(OH)2 is a complete reaction. In a neutralization reaction, salts are formed from equal weights of acid and base. 

Is HCl and Mg(OH)2 an Exothermic or Endothermic reaction

The reaction of  HCl and Mg(OH)2 is an exothermic reaction because heat is released during the reaction.

Is HCl and Mg(OH)2 a Redox reaction

The reaction of HCl and Mg(OH)2 is not a redox reaction. For a redox reaction to take place, changes in oxidation states are required.

Is HCl and Mg(OH)2 a Precipitation reaction

The reaction of HCl and Mg(OH)2 is not a precipitation reaction. The reaction between HCl with Mg(OH)2 does not result in the formation of a precipitate.

Is HCl and Mg(OH)2 a Reversible or Irreversible reaction

The reaction of HCl and Mg(OH)is an irreversible reaction. MgCl2, a salt produced by this acid-base reaction, is highly soluble in water and cannot be converted back into Mg(OH)2.

Is HCl and Mg(OH)2 a Displacement reaction

The reaction of HCl and Mg(OH)2 is not a displacement reaction, it is called a double displacement reaction.

Mg(OH)2(s) + 2HCl(aq)→MgCl2(aq) + 2H2O(l)

reaction wp
Double displacement reaction

Conclusion

HCl is a potent acid that is colorless and has an unpleasant smell. Magnesium hydroxide and hydrochloric acid combine to form a neutralization reaction, which is also used for wastewater treatment, to control the pH of the soil.