Difference Between Complete Ionic and Net Ionic Equation

Key Difference – Complete Ionic vs Net Ionic Equation
 

Chemical reactions are interactions between chemical compounds to form new compounds or to rearrange their chemical structure. The compounds that undergo a certain chemical reaction is called a reactant, and what we get at the end is called the product. A chemical equation is a representation of the chemical reaction using chemical symbols. The chemical equation shows what the reactants are and what are the products. Complete ionic equation and net ionic equation are two ways of representing a chemical reaction. The key difference between Complete ionic and net ionic equation is that complete ionic equation gives all the ionic species participated in the chemical reaction whereas net ionic reaction gives the chemical species participated in the formation of the final product.

CONTENTS

1. Overview and Key Difference
2. What is Complete Ionic Equation
3. What is Net Ionic Equation
4. Side by Side Comparison – Complete Ionic vs Net Ionic Equation in Tabular Form
5. Summary

What is Complete Ionic Equation?

The complete ionic equation is a chemical equation that explains the chemical reaction, clearly indicating the ionic species present in a solution. An ionic species is either an anion (negatively charged species) or a cation (positively charged species). In contrast, a complete molecular equation gives the molecules take part in a chemical reaction. Let us consider an example to understand this concept.

 The reaction between NaCl (sodium chloride) and AgNO₃ (silver nitrate) forms a white coloured precipitate. The molecular equation for the reaction is as below.

NaCl     +     AgNO₃       →          AgCl     +    NaNO₃

This reaction takes place in an aqueous medium. NaCl dissociates into cations and anions in the aqueous solution as below.

NaCl    →      Na⁺   +   Cl^–

Then these ions undergo reaction with silver nitrate forming the AgCl white precipitate. According to the above equation, after the reaction, NaNO₃ is formed as a byproduct. However, what actually happens is, Na⁺ and NO₃^– ions are released to the aqueous medium, and they stay in their ionic form. Then the complete ionic equation for this chemical reaction can be written as,

Na⁺   +   Cl^–  +   Ag⁺   +   NO₃^–     →      AgCl    +    Na⁺   +   NO₃^–

This equation gives the full details about the reaction mixture and the final product as well. The complete ionic equation of a reaction can be used to get the net ionic equation.

What is Net Ionic Equation?

The net ionic equation is a chemical equation that shows the ions participated in the formation of the final product. This equation can be obtained from the complete ionic equation by cancelling out the similar ions from the two sides of the complete ionic equation. Hence, the net ionic equation does not give details about all the ionic species present in the reaction mixture. For the reaction between NaCl and AgNO₃, the net ionic equation can be obtained as follows.

The complete ionic equation:

Na⁺   +   Cl^–  +   Ag⁺   +   NO₃^–     →      AgCl    +    Na⁺   +   NO₃^–

The net ionic equation:

Na⁺   +   Cl^–  +   Ag⁺   +   NO₃^–     →      AgCl    +    Na⁺   +   NO₃^–

Cl^–    +    Ag⁺   →      AgCl   ^–

The above net ionic equation indicates Chloride ions and silver cations are responsible for the formation of AgCl white precipitate and this does not include the remaining ions (Na⁺ and NO₃^–). The eliminated ions are known as “spectator ions” which do not involve in the formation of a precipitate.

What is the Difference Between Complete Ionic and Net Ionic Equation?

Summary – Complete Ionic vs Net Ionic Equation

The complete ionic equation and net ionic equation are two forms of chemical equations that are used to describe the chemical species that are present in a reaction mixture or the chemical species that are participated in a certain chemical reaction. The difference between Complete ionic and net ionic equation is that complete ionic equation gives all the ionic species participated in the chemical reaction whereas net ionic reaction gives the chemical species participated in the formation of the final product.

Reference:

1.“Complete Molecular, Complete Ionic and Net Ionic.” ChemTeam: Equations. Available here  
2.“How to Cancel Spectator Ions to Find a Net Ionic Equation.” Dummies. Available here  

Image Courtesy:

1.’Silver chloride (AgCl)’By Luisbrudna – Own work, (CC BY-SA 4.0) via Commons Wikimedia