What are the products of the neutralization reaction between hydrochloric acid and magnesium hydroxide?

1 Answer
May 22, 2014

The products are magnesium chloride and water.

Hydrochloric acid is a strong acid. It reacts completely with water to form hydronium ions and chloride ions.

HCl + H₂O → H₃O⁺ + Cl⁻

The equation is often simplified by omitting the water

HCl → H⁺ + Cl⁻

Magnesium hydroxide, Mg(OH)₂, is a strong base. It contains hydroxide ions, OH⁻, and magnesium ions, Mg²⁺.

When HCl reacts with water, the hydrogen ions react with the hydroxide ions to form water:

H⁺ + OH⁻ → H₂O

Thus, the reaction between HCl and Mg(OH)₂ is then:

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

The products are magnesium chloride and water.

Using ions, the reaction is:

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

We can cancel Cl⁻ from each side of the equation. This gives the net ionic equation

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