Question

Write a balanced equation Magnesium metal is treated with dilute Hydrochloric acid.

Answer 1

Step 1: Reacting to the given molecules:

• The reaction between Magnesium and Hydrochloric acid combines to form a salt of Magnesium Chloride and release Hydrogen gas. This reaction is an example of a single replacement.
• Hydrochloric acid reacts with Magnesium to form Magnesium Chloride and release Hydrogen gas.
• The unbalanced chemical equation can be written as:
• $$\begin{gathered} \mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Mg}\mathbf{}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{}\mathbf{+}\mathbf{}\mathbf{HCl}\mathbf{}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{}\mathbf{\to }\mathbf{}{\mathbf{MgCl}}_{\mathbf{2}}\mathbf{}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{}\mathbf{+}\mathbf{}{\mathbf{H}}_{\mathbf{2}}\mathbf{}\mathbf{\left(}\mathbf{g}\mathbf{\right)} \\ \mathbf{Magesium}\mathbf{}\mathbf{Hydrochloric}\mathbf{}\mathbf{}\mathbf{Magnesium}\mathbf{} \\ \mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Acid}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Chloride} \end{gathered}$$

Step 2: Balancing the chemical equation

• The total number of atoms of each element on the reactant side and the product side must be compared.
• On the reactant side: $\mathbf{1}$ Magnesium atom from $\mathbf{Mg}$, $\mathbf{1}$ atom of Hydrogen from $\mathbf{HCl}$ and $\mathbf{1}$ Chlorine atom from $\mathbf{HCl}$
• On the product side: $\mathbf{1}$ Magnesium atom from ${\mathbf{MgCl}}_{\mathbf{2}}$, $\mathbf{2}$ Hydrogen atoms from ${\mathbf{H}}_{\mathbf{2}}$ and $\mathbf{2}$ Chlorine atoms from ${\mathbf{MgCl}}_{\mathbf{2}}$

Step 3: Balancing the reactant molecules by multiplying $\mathbf{2}$ by $\mathbf{HCl}$

• The chemical reaction is as follows:
• $$\begin{gathered} \mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Mg}\mathbf{}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{}\mathbf{+}\mathbf{}\mathbf{2}\mathbf{}\mathbf{HCl}\mathbf{}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{}\mathbf{\to }\mathbf{}{\mathbf{MgCl}}_{\mathbf{2}}\mathbf{}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{}\mathbf{+}\mathbf{}{\mathbf{H}}_{\mathbf{2}}\mathbf{}\mathbf{\left(}\mathbf{g}\mathbf{\right)} \\ \mathbf{Magesium}\mathbf{}\mathbf{Hydrochloric}\mathbf{}\mathbf{}\mathbf{Magnesium}\mathbf{} \\ \mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Acid}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Chloride} \end{gathered}$$
• On the reactant side: $\mathbf{1}$ Magnesium atom from $\mathbf{Mg}$, $\mathbf{2}$ atom of Hydrogen from $\mathbf{HCl}$ and $\mathbf{2}$ Chlorine atom from $\mathbf{HCl}$.
• On the product side: $\mathbf{1}$ Magnesium atom from ${\mathbf{MgCl}}_{\mathbf{2}}$, $\mathbf{2}$ Hydrogen atoms from ${\mathbf{H}}_{\mathbf{2}}$ and $\mathbf{2}$ Chlorine atoms from ${\mathbf{MgCl}}_{\mathbf{2}}$ .
• After multiplication, we have an equal number of molecules on both sides of the reaction.

Step 4: Balanced chemical equation is as follows:

1. Therefore, the balanced equation is :
2. $$\begin{gathered} \mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Mg}\mathbf{}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{}\mathbf{+}\mathbf{}\mathbf{HCl}\mathbf{}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{}\mathbf{\to }\mathbf{}{\mathbf{MgCl}}_{\mathbf{2}}\mathbf{}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{}\mathbf{+}\mathbf{}{\mathbf{H}}_{\mathbf{2}}\mathbf{}\mathbf{\left(}\mathbf{g}\mathbf{\right)} \\ \mathbf{Magesium}\mathbf{}\mathbf{Hydrochloric}\mathbf{}\mathbf{}\mathbf{Magnesium}\mathbf{} \\ \mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Acid}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Chloride} \end{gathered}$$

Hence, the equation is balanced.