Question

How do you write chemical equation for the neutralization of nitric acid, HNO3, with magnesium hydroxide, Mg(OH)2, first with spectator ions and then without spectator ions?

Answer 1

First you write the "molecular" equation, then the ionic equation, and finally the net ionic equation.

Explanation:

You can read about these equations at

http://socratic.org/questions/what-is-the-net-ionic-equation-of-the-reaction-of-fecl2-with-naoh

Here are the steps for your reaction.

1. Write the molecular equation

We write the equation as if all the reactants were molecules.

2HNO₃(aq) + Mg(OH)₂(s) → 2H₂O(l) + Mg(NO₃)₂(aq

2. Write the ionic equation

We write all the soluble strong electrolytes as ions. H₂O is a weak electrolyte, so we write it as a molecule. Mg(OH)₂ is insoluble, so we write it as a molecule as well.

2H⁺(aq) + 2NO₃⁻(aq) + Mg(OH)₂(s) → 2H₂O(l) + Mg²⁺(aq) + 2NO₃⁻(aq)

3. Write the net ionic equation

Here, we cancel all species that appear on both sides of the equation. We cancel the NO₃⁻ ions.

The net ionic equation is

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