Question

What is the chemical equation for the neutralization of nitric acid, $ ~HN{{O}_{3}} $ with Magnesium Hydroxide, $ Mg{{\left( OH \right)}_{2}} $ first with spectator ions and them without spectator ions?

Answer 1

Hint: We know that magnesium metal reacts with very dilute nitric acid to produce a highly flammable gas. We must know which of the given gases is flammable. The nitric acid in the reaction loses an atom and forms another molecule and one can analyze this behavior and relate them with the chemical concepts.

Complete answer:
We know that nitric acid $ \left( ~HN{{O}_{3}} \right) $ is a very strong oxidizing agent. It is a strong acid and thus, it dissociates completely. Nitric acid can be concentrated or dilute depending on its concentration. Concentrated nitric acid on reaction with metals generally gives metal nitrates. Along with metal nitrates it produces nitrogen dioxide and water. Dilute nitric acid on reaction with metals generally gives metal nitrates.
Along with metal nitrates it produces highly flammable hydrogen gas. We know that magnesium belongs to group two of the periodic table. Magnesium is highly reactive in nature. When magnesium metal reacts with very dilute nitric acid it gives magnesium nitrate $ \left( Mg{{\left( N{{O}_{3}} \right)}_{2}} \right). $ Along with magnesium nitrate highly flammable hydrogen gas $ \left( {{H}_{2}} \right) $ is also produced.
Write the molecular equation: We write the equation as if all the reactants were molecules. $ 2HN{{O}_{3\left( aq \right)}}+Mg{{\left( OH \right)}_{2\left( s \right)}}\to 2{{H}_{2}}{{O}_{\left( l \right)}}+Mg{{\left( N{{O}_{3}} \right)}_{2}}_{\left( aq \right)} $
Write the ionic equation: We write all the soluble strong electrolytes as ions. $ {{H}_{2}}O $ is a weak electrolyte, so we write it as a molecule. $ Mg{{\left( OH \right)}_{2}} $ is insoluble, so we write it as a molecule as well. $ 2H_{\left( aq \right)}^{+}+2NO_{3\left( aq \right)}^{-}+Mg{{\left( OH \right)}_{2\left( s \right)}}\to \text{ }2{{H}_{2}}{{O}_{\left( l \right)}}+Mg_{\left( aq \right)}^{2+}+2NO_{3\left( aq \right)}^{-} $
Write the net ionic equation: Here, we cancel all species that appear on both sides of the equation. We cancel the $ NO_{3}^{-} $ ions. Therefore, net ionic equation is $ 2H_{\left( aq \right)}^{+}+Mg{{\left( OH \right)}_{2\left( s \right)}}\to \text{ }2{{H}_{2}}{{O}_{\left( l \right)}}+Mg_{\left( aq \right)}^{^{2+}} $ .

Note:
Remember that the oxidation numbers represent the potential charge present on an atom in its ionic form. If the atom's oxidation is decreased in a reaction, then it is said to get reduced. If it increases, then the atom is said to get oxidized.