Question

Write the balanced equation for the following reaction.

Action Hydrochloric acid ($\mathbf{HCl}$) on Sodium sulfide.

Answer 1

Step1: Reacting the given molecules:

• Hydrogen chloride and Sodium sulfide react together to form Sodium chloride and Hydrogen sulphide.
• The unbalanced chemical equation is
• $$\begin{gathered} {\mathrm{Na}}_2\mathrm{S}\left(s\right)+\mathrm{HCl}(dil\mathit{.})\to \mathrm{NaCl}\left(aq\right)+{\mathrm{H}}_2\mathrm{S}\left(g\right)\uparrow \\ \mathrm{Sodium}\mathrm{Hydrogen}\mathrm{Sodium}\mathrm{Hydrogen} \\ \mathrm{sulfide}\mathrm{chloride}\mathrm{chloride}\mathrm{sulfide} \end{gathered}$$

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: $\mathbf{2}$ Sodium atom from ${\mathbf{Na}}_{\mathbf{2}}\mathbf{S}$, $\mathbf{1}$ Sulfur atom from ${\mathbf{Na}}_{\mathbf{2}}\mathbf{S}$, $\mathbf{1}$ from $\mathbf{HCl}$ and $\mathbf{1}$ Chlorine atom from $\mathbf{HCl}$
• On the product side: $\mathbf{1}$ Sodium atom from $\mathbf{NaCl}$, $\mathbf{1}$ Chlorine atoms from $\mathbf{NaCl}$, $\mathbf{2}$ Hydrogen atoms from ${\mathbf{H}}_{\mathbf{2}}\mathbf{S}$ and $\mathbf{1}$ Sulfur atom from ${\mathbf{H}}_{\mathbf{2}}\mathbf{S}$.

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

• The chemical reaction is as follows:
• $$\begin{gathered} \mathit{N}{\mathit{a}}_{\mathbf{2}}\mathbf{S}\mathbf{}\mathbf{\left(}\mathit{s}\mathbf{\right)}\mathbf{+}\mathbf{}\mathbf{2}\mathbf{}\mathit{H}\mathit{C}\mathit{l}\mathbf{}\mathbf{(}\mathit{d}\mathit{i}\mathit{l}\mathit{.}\mathbf{)}\mathbf{}\mathbf{\to }\mathbf{}\mathbf{2}\mathbf{}\mathit{N}\mathit{a}\mathit{C}\mathit{l}\mathbf{}\mathbf{\left(}\mathit{a}\mathit{q}\mathbf{\right)}\mathbf{}\mathbf{+}\mathbf{}{\mathbf{H}}_{\mathbf{2}}\mathbf{S}\mathbf{}\mathbf{\left(}\mathit{g}\mathbf{\right)}\mathbf{}\mathbf{\uparrow } \\ \mathit{S}\mathit{o}\mathit{d}\mathit{i}\mathit{u}\mathit{m}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathit{H}\mathit{y}\mathit{d}\mathit{r}\mathit{o}\mathit{g}\mathit{e}\mathit{n}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathit{S}\mathit{o}\mathit{d}\mathit{i}\mathit{u}\mathit{m}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathit{H}\mathit{y}\mathit{d}\mathit{r}\mathit{o}\mathit{g}\mathit{e}\mathit{n} \\ \mathit{s}\mathit{u}\mathit{l}\mathit{f}\mathit{i}\mathit{d}\mathit{e}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathit{c}\mathit{h}\mathit{l}\mathit{o}\mathit{r}\mathit{i}\mathit{d}\mathit{e}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathit{c}\mathit{h}\mathit{l}\mathit{o}\mathit{r}\mathit{i}\mathit{d}\mathit{e}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathit{s}\mathit{u}\mathit{l}\mathit{f}\mathit{i}\mathit{d}\mathit{e} \end{gathered}$$
• On the reactant side: $\mathbf{2}$ Sodium atom from ${\mathbf{Na}}_{\mathbf{2}}\mathbf{S}$, $\mathbf{1}$ Sulfur atom from ${\mathbf{Na}}_{\mathbf{2}}\mathbf{S}$, $\mathbf{2}$ from $\mathbf{HCl}$ and $\mathbf{2}$ Chlorine atom from $\mathbf{HCl}$
• On the product side: $\mathbf{2}$ Sodium atom from $\mathbf{NaCl}$, $\mathbf{2}$ Chlorine atoms from $\mathbf{NaCl}$, $\mathbf{2}$ Hydrogen atoms from ${\mathbf{H}}_{\mathbf{2}}\mathbf{S}$ and $\mathbf{1}$ Sulfur atom from ${\mathbf{H}}_{\mathbf{2}}\mathbf{S}$.
• After calculation, we have an equal number of molecules on both sides of the reaction

Step 4: Balanced chemical equation is as follows:

• Then the balanced chemical equation can be provided as,

1. $$\begin{gathered} \mathit{N}{\mathit{a}}_{\mathbf{2}}\mathbf{S}\mathbf{}\mathbf{\left(}\mathit{s}\mathbf{\right)}\mathbf{+}\mathbf{}\mathbf{2}\mathbf{}\mathit{H}\mathit{C}\mathit{l}\mathbf{}\mathbf{(}\mathit{d}\mathit{i}\mathit{l}\mathit{.}\mathbf{)}\mathbf{}\mathbf{\to }\mathbf{}\mathbf{2}\mathbf{}\mathit{N}\mathit{a}\mathit{C}\mathit{l}\mathbf{}\mathbf{\left(}\mathit{a}\mathit{q}\mathbf{\right)}\mathbf{}\mathbf{+}\mathbf{}{\mathbf{H}}_{\mathbf{2}}\mathbf{S}\mathbf{}\mathbf{\left(}\mathit{g}\mathbf{\right)}\mathbf{}\mathbf{\uparrow } \\ \mathit{S}\mathit{o}\mathit{d}\mathit{i}\mathit{u}\mathit{m}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathit{H}\mathit{y}\mathit{d}\mathit{r}\mathit{o}\mathit{g}\mathit{e}\mathit{n}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathit{S}\mathit{o}\mathit{d}\mathit{i}\mathit{u}\mathit{m}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathit{H}\mathit{y}\mathit{d}\mathit{r}\mathit{o}\mathit{g}\mathit{e}\mathit{n} \\ \mathit{s}\mathit{u}\mathit{l}\mathit{f}\mathit{i}\mathit{d}\mathit{e}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathit{c}\mathit{h}\mathit{l}\mathit{o}\mathit{r}\mathit{i}\mathit{d}\mathit{e}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathit{c}\mathit{h}\mathit{l}\mathit{o}\mathit{r}\mathit{i}\mathit{d}\mathit{e}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathit{s}\mathit{u}\mathit{l}\mathit{f}\mathit{i}\mathit{d}\mathit{e} \end{gathered}$$

Hence, the equation is balanced.