Chapter 9.3, Problem 46PP

Interpretation Introduction

Interpretation:

The chemical, complete ionic and net ionic equation of reaction of sulphuric acid with aqueous sodium cyanide to produce hydrogen cyanide gas and aqueous sodium sulphate needs to be determined.

Concept introduction:

Chemical equation is the balanced chemical equation which shows the reactants and products using their chemical formulas. An ionic equation represents all the particles in a solution according to their existence and net ionic equations are the ionic equations that include only the particles participating in the reaction.

Answer to Problem 46PP

Chemical equation is represented as follows:

${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}(aq)+2\text{NaCN}\text{(}aq\text{)}\to 2\text{HCN}\text{(}g\text{)}\text{+}{\text{Na}}_{\text{2}}{\text{SO}}_{\text{4}}(aq)$

Complete ionic equation is,

${\text{2H}}^{+}(aq)+{\text{SO}}_{\text{4}}{}^{2-}(aq)+2{\text{Na}}^{+}\text{+}{\text{2CN}}^{-}\text{(}aq\text{)}\to 2\text{HCN}\text{(}g\text{)}\text{+}2{\text{Na}}^{+}\text{(}aq\text{)+}{\text{SO}}_{\text{4}}{}^{2-}(aq)$

Net ionic equation is,

${\text{H}}^{+}(aq)\text{+}{\text{CN}}^{-}\text{(}aq\text{)}\to \text{HCN}\text{(}g\text{)}$

Explanation of Solution

Chemical equation shows the reactants and products using chemical formulas. So, chemical equation for reaction of sulphuric acid with aqueous sodium cyanide to produce hydrogen cyanide gas and aqueous sodium sulphate is,

${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}(aq)+2\text{NaCN}\text{(}aq\text{)}\to 2\text{HCN}\text{(}g\text{)}\text{+}{\text{Na}}_{\text{2}}{\text{SO}}_{\text{4}}(aq)$

The complete ionic equation shows ions of reactants and products. So, the complete ionic equation is,

${\text{2H}}^{+}(aq)+{\text{SO}}_{\text{4}}{}^{2-}(aq)+2{\text{Na}}^{+}\text{+}{\text{2CN}}^{-}\text{(}aq\text{)}\to 2\text{HCN}\text{(}g\text{)}\text{+}2{\text{Na}}^{+}\text{(}aq\text{)+}{\text{SO}}_{\text{4}}{}^{2-}(aq)$

In net ionic equation, the common ions in both sides of the reaction are cancelled. So, the net ionic equation is,

$\begin{array}{l}{\text{2H}}^{+}(aq)+\cancel{{\text{SO}}_{\text{4}}{}^{2-}(aq)}+\cancel{2{\text{Na}}^{+}}\text{+}{\text{2CN}}^{-}\text{(}aq\text{)}\to 2\text{HCN}\text{(}g\text{)}\text{+}\cancel{2{\text{Na}}^{+}}\text{+}\cancel{{\text{SO}}_{\text{4}}{}^{2-}(aq)}\\ {\text{2H}}^{+}(aq)\text{+}{\text{2CN}}^{-}\text{(}aq\text{)}\to 2\text{HCN}\text{(}g\text{)}\\ {\text{H}}^{+}(aq)\text{+}{\text{CN}}^{-}\text{(}aq\text{)}\to \text{HCN}\text{(}g\text{)}\end{array}$

Conclusion

To show the details of reactions that involves ions in aqueous solutions, the ionic equations, such as, complete ionic equation and net ionic equations are used.