No, sodium nitrate does not react with potassium chloride when these two common salts are mixed in an aqueous solution. This is because all potential products remain dissolved in the solution, meaning there is no driving force for a chemical reaction to occur.
As clearly stated by "Dr. B" in the provided video reference, when discussing the net ionic equation for KCl + NaNO3, the conclusion is direct: "really there's no reaction." This concise assessment accurately reflects the chemical behavior of these two compounds when combined.
Understanding the Potential Reaction
When considering the mixing of two salt solutions, chemists typically look for a double displacement (also known as metathesis) reaction. In such a reaction, the cations (positively charged ions) and anions (negatively charged ions) switch partners.
For sodium nitrate ($NaNO_3$) and potassium chloride ($KCl$), the potential products would be:
- Reactants:
- Sodium Nitrate ($NaNO_3$)
- Potassium Chloride ($KCl$)
- Potential Products (after swapping ions):
- Potassium Nitrate ($KNO_3$)
- Sodium Chloride ($NaCl$)
Why No Reaction Occurs
The key reason for the absence of a reaction lies in the solubility of these potential products in water. For a double displacement reaction to produce a visible change or a significant chemical transformation, at least one of the products must:
- Form a precipitate (an insoluble solid).
- Produce a gas that escapes the solution.
- Form a stable molecular compound like water (as in an acid-base neutralization).
Let's examine the solubility of the potential products:
| Compound | Chemical Formula | Solubility in Water |
|---|---|---|
| Potassium Nitrate | $KNO_3$ | Soluble |
| Sodium Chloride (Table Salt) | $NaCl$ | Soluble |
According to general solubility rules:
- All nitrates ($NO_3^-$) are soluble.
- All compounds containing alkali metal ions ($Na^+$, $K^+$) are soluble.
Since both potassium nitrate and sodium chloride are highly soluble in water, they remain dissociated into their respective ions in the solution.
The Net Ionic Equation Perspective
The concept of a net ionic equation further clarifies why no reaction takes place:
-
Molecular Equation: This shows the full chemical formulas of the reactants and products.
$KCl{(aq)} + NaNO{3(aq)} \rightarrow KNO{3(aq)} + NaCl{(aq)}$ -
Complete Ionic Equation: This shows all soluble ionic compounds dissociated into their constituent ions.
$K^+{(aq)} + Cl^-{(aq)} + Na^+_{(aq)} + NO3^-{}{(aq)} \rightarrow K^+_{(aq)} + NO3^-{}{(aq)} + Na^+{(aq)} + Cl^-{(aq)}$ -
Net Ionic Equation: To derive this, we cancel out the "spectator ions"—those ions that appear unchanged on both sides of the equation. In this case, every ion ($K^+$, $Cl^-$, $Na^+$, $NO_3^-$) is a spectator ion because they are present as dissolved ions before and after mixing.
Therefore, the net ionic equation is simply: No Reaction
This means that simply mixing aqueous solutions of sodium nitrate and potassium chloride together will not result in a new compound being formed, no precipitate will appear, and no gas will evolve. The ions will remain dissolved in the solution, essentially just mixing without undergoing a chemical change.
