# Question Video: Writing a Net Ionic Equation for the Reaction of Chlorine Water with Aqueous Sodium Bromide Chemistry • 10th Grade

Consider the following equation: Cl₂ (aq) + 2NaBr (aq) ⟶ Br2 (aq) + 2NaCl (aq). What is the net ionic equation for the displacement reaction between aqueous chlorine and sodium bromide?

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### Video Transcript

Consider the following equation. Cl2 aqueous plus two NaBr aqueous react to form Br2 aqueous plus two NaCl aqueous. What is the net ionic equation for the displacement reaction between aqueous chlorine and sodium bromide?

The provided equation is a balanced molecular equation. It shows the reaction between aqueous chlorine, often called chlorine water, and an aqueous solution of sodium bromide. The products of the reaction are aqueous diatomic bromine and aqueous sodium chloride. Our job in this question is to write a net ionic equation for this displacement reaction.

There are basic rules that we can use to transform a molecular equation into an ionic equation and then into a net ionic equation. First, we will need to split any acids or ionic compounds that are dissolved in aqueous solutions into ions. The reactant sodium bromide, or NaBr, is an ionic compound dissolved in an aqueous solution. The product sodium chloride, or NaCl, is also an ionic compound dissolved in an aqueous solution.

Let’s get started by writing the reactants of the ionic equation. Because there were two equivalents of aqueous sodium bromide in the molecular equation, in our ionic equation, we will write this as two sodium ions plus two bromide ions. In the ionic equation, we must also include the charges of any dissolved ions and use the state symbol aq after each ion symbol.

Now, let’s write the products of the ionic equation. Because there were two equivalents of aqueous sodium chloride in the molecular equation, in our ionic equation, we will write this as two sodium ions plus two chloride ions. For each ion, we write the ionic charge as a superscript and finish by writing the state symbol aq. Now that we have an ionic equation, we need to convert it into a net ionic equation. To do so, we need to remove ions that do not participate in the chemical reaction from our ionic equation. These ions are called spectator ions.

During the chemical reaction, diatomic chlorine molecules react to form chloride ions and displace bromide ions from the sodium bromide solution. The bromide ions also react to form diatomic bromine molecules. In contrast, the sodium ions are spectator ions and do not participate in the chemical reaction. Therefore, the sodium ions should not be included in our net ionic equation.

In conclusion, the net ionic equation for the provided reaction is Cl2 aqueous plus 2Br− aqueous react to form Br2 aqueous plus two Cl− aqueous.