A net ionic equation helps chemists represent the steps in a chemical reaction. In solution chemistry, one part of a chemical reacts with a part of another chemical. In a solution, ions, or charged particles, can disassociate from one another. After one chemical disassociates from the parent molecule, it is available to interact with the other reactant. Mixing acetic acid and sodium hydroxide together will yield water and sodium acetate. Because the sodium acetate is a salt, it will disassociate in water – leaving it in its ionic form. Spectator ions, in this case sodium, are left out of the final equation because they are in the ionic state before and after the reaction is completed.
Writing the Equation
First write the standard chemical equation of acetic acid reacting with sodium hydroxide to form water and sodium acetate. It should be written as CH3COOH + NaOH > H20 + CH3COONa.
Secondly, copy the equation below what is written, except write out the ionic form of each molecule on the left hand of the equation. Acetic acid is a weak acid that will not disassociate significantly; it is kept in the whole form. Sodium hydroxide will separate to form sodium (+) and a hydroxide group (-).
Thirdly, complete the rest of the equation by writing out the right-hand side of the equation. Water should be left as H2O; sodium acetate should be written as an acetate ion (-) and a sodium ion (+).
Fourthly, cross out the items that are found on both sides of the reaction. Sodium is found in the same form in both sides of the equation, therefore, it is crossed out. These items are known as spectator ions.
Finally, write out the final net ionic equation, omitting the crossed out ions in this step. The equation should be written as (CH3COOH) + (OH-) > (H2O) + (CH3COO-).
Because acetic acid is a weak acid by itself, it will stay in the whole form until it reacts with sodium hydroxide. Remember to write the proper ionic charge with every reactant and product in the equation.
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