# Question #71391

Mar 27, 2017

No, the solution is not saturated.

#### Explanation:

Your tool of choice here will be the solubility graph of potassium nitrate, ${\text{KNO}}_{3}$, which looks like this The curve shows you the amount of potassium nitrate than can be dissolved per $\text{100 mL}$ of water at various temperatures in order to create a saturated solution of potassium nitrate.

For the sake of simplicity, let's assume that the graph shows the solubility of the salt per $\text{100 g}$ of water.

Now, if you draw a vertical line starting from ${90}^{\circ} \text{C}$, you will notice that it intersects the curve at approximately $\text{200 g}$ of potassium nitrate per $\text{100 g}$ of water.

This represents the solubility of the salt at this temperature. In other words, you can only hope to dissolve $\text{200 g}$ of potassium nitrate for every $\text{100 g}$ of water at ${90}^{\circ} \text{C}$.

Your solution contains $\text{30 g}$ of potassium nitrate per $\text{100 g}$ of water at this temperature, so it will not be saturated because you can dissolve an additional

${\text{200 g"color(white)(.) - color(white)(.)"30 g" = "170 g KNO}}_{3}$

for every $\text{100 g}$ of water at this temperature. You can thus say that the solution is unsaturated.