What is the overall equation, the complete ionic equation, and the net ionic equation for the reaction that occurs when aqueous solutions of cobalt (II) bromide and sodium hydroxide are mixed?

To determine the overall equation, complete ionic equation, and net ionic equation for the reaction between cobalt (II) bromide (CoBr2) and sodium hydroxide (NaOH), we need to first understand the chemical formulas of each compound:

- Cobalt (II) bromide: CoBr2
- Sodium hydroxide: NaOH

Let's break down the process step by step:

Step 1: Write the overall equation:
The overall equation represents the reaction in its simplest form, without separating the reactants and products into ions. To write the overall equation, we combine the reactants and products:
CoBr2(aq) + 2NaOH(aq) → Co(OH)2(s) + 2NaBr(aq)

Step 2: Write the complete ionic equation:
The complete ionic equation represents the reaction by separating all the reactants and products into their respective ions. Write the equation using the formulas of each compound and break them into their ionic components:
Co2+(aq) + 2Br-(aq) + 2Na+(aq) + 2OH-(aq) → Co(OH)2(s) + 2Na+(aq) + 2Br-(aq)

Step 3: Write the net ionic equation:
The net ionic equation focuses on the essential components of the reaction, excluding any spectator ions. Spectator ions are those that appear on both sides of the equation and do not participate in the actual reaction. To write the net ionic equation, remove the spectator ions from the complete ionic equation:
Co2+(aq) + 2OH-(aq) → Co(OH)2(s)

In the net ionic equation, only the cobalt ion (Co2+) and hydroxide ion (OH-) are involved, representing the actual chemical change occurring during the reaction.

Summary:
Overall equation: CoBr2(aq) + 2NaOH(aq) → Co(OH)2(s) + 2NaBr(aq)
Complete ionic equation: Co2+(aq) + 2Br-(aq) + 2Na+(aq) + 2OH-(aq) → Co(OH)2(s) + 2Na+(aq) + 2Br-(aq)
Net ionic equation: Co2+(aq) + 2OH-(aq) → Co(OH)2(s)