Question

Complete and balance the following reaction:

${\mathrm{K}}_2\mathrm{O}+\mathrm{HCl}\to$

Answer 1

• When metallic oxide reacts with Hydrochloric acid ($\mathbf{HCl}$) it forms its respective chloride along with water.
• General reaction between Metal oxide and Hydrochloric acid is given below :

$$\begin{gathered} \mathrm{Metal}+\mathrm{Hydrochloric}\to \mathrm{Metal}+\mathrm{Water} \\ \mathrm{oxide}\mathrm{acid}(dil.)\mathrm{chloride} \end{gathered}$$

Step 1: Reacting the given molecules:

• Potassium oxide (${\mathbf{K}}_{\mathbf{2}}\mathbf{O}$) react with Hydrogen chloride ($\mathbf{HCl}$) to form Potassium chloride ($\mathbf{KCl}$) and water.
• Complete reaction between Copper Oxide and Hydrochloric acid is $\underset{(\mathrm{Potassium}\mathrm{oxide})}{{\mathrm{K}}_2\mathrm{O}\left(\mathit{s}\right)}+\underset{(\mathrm{Hydrogen}\mathrm{chloride})}{\mathrm{HCl}\left(aq\right)}\to \underset{(\mathrm{Potassium}\mathrm{chloride})}{\mathrm{KCl}(\mathit{a}\mathit{q}\mathit{)}}+\underset{\left(\mathrm{water}\right)}{{\mathrm{H}}_2\mathrm{O}\left(aq\right)}$

Step 2: Balancing the chemical equation

• The given reaction is unbalanced to balance such a reaction we first calculate the number of molecules on both sides of the reaction.
• On the reactant side: 2 Potassium and 1 Oxygen are present in the Potassium oxide.
• Similarly, 1 Hydrogen and 1 Chlorine are present in Hydrogen chloride.
• On the product side: 1 Potassium and 1 Chlorine are present in Potassium chloride
• Similarly, 2 Hydrogen and 1 oxygen are present in the water molecule.

Step 3: Balancing the reactant molecules: Multiplying 2 by Hydrogen chloride.

• The chemical equation is as follows: $\underset{(\mathrm{Potassium}\mathrm{oxide})}{{\mathrm{K}}_2\mathrm{O}\left(s\right)}+\underset{(\mathrm{Hydrogen}\mathrm{chloride})}{2\mathrm{HCl}\left(aq\right)}\to \underset{(\mathrm{Potassium}\mathrm{chloride})}{\mathrm{KCl}\left(aq\right)}+{\mathrm{H}}_2\mathrm{O}\left(aq\right)$

Step 3: Balancing the product molecules: Multiplying 2 by Potassium chloride

• The chemical equation is as follows: $\underset{(\mathrm{Potassium}\mathrm{oxide})}{{\mathrm{K}}_2\mathrm{O}\left(s\right)}+\underset{(\mathrm{Hydrogen}\mathrm{chloride})}{2\mathrm{HCl}\left(aq\right)}\to \underset{(\mathrm{Potassium}\mathrm{chloride})}{2\mathrm{KCl}\left(aq\right)}+{\mathrm{H}}_2\mathrm{O}\left(aq\right)$
• Thus, we get an equal number of molecules on both sides of the reaction.
• On the reactant side: 2 Potassium and 1 Oxygen are present in the Potassium oxide.
• Similarly, 2 Hydrogen and 2 Chlorine are present in Hydrogen chloride.
• On the product side: 2 Potassium and 2 Chlorine are present in Potassium chloride
• Similarly, 2 Hydrogen and 1 Oxygen are present in the Water molecule.

Hence the equation is balanced.