Types of Aqueous Solutions - Online Tutor, Practice Problems & Exam Prep

Solutions are homogeneous mixtures where solutes dissolve in solvents, reaching a solution equilibrium where dissolution and recrystallization rates are equal. The equilibrium concentration is the maximum amount of dissolved solute at a given temperature. Solutions can be categorized as saturated, unsaturated, or supersaturated. Saturated solutions have the maximum solute dissolved, reaching equilibrium concentration. Unsaturated solutions can still dissolve more solute, being below equilibrium concentration. Supersaturated solutions contain more solute than the equilibrium allows and are unstable unless conditions like temperature are altered to increase solubility. Understanding these solution types is crucial for predicting solubility behaviors and preparing solutions with desired concentrations.

Types of Aqueous Solutions Concept 1

At this point, we know that solutions represent homogeneous mixtures, but what we need to realize is that there are different types of solutions that exist as well. Now we're going to say here that when solid solutes dissolve in a solvent such as water and equilibrium takes place, we're going to say here we have what's called a solution equilibrium. This is when the rate of dissolution and recrystallization of solutes are equal.

Now dissolution we know that means that our solid solute breaks up into ions. What recrystallization will be the opposite of that? That's the process of where our dissolved solute starts reforming back into a solid. Now there are three possible aqueous solutions that are created. There's a saturated and unsaturated or a super saturated solution.

Now here when we talk about equilibrium concentration, this is just the maximum amount of dissolved solute present in solution at a given temperature. So keep in mind we have solutions which are homogeneous mixtures and these solutions can either be saturated, unsaturated or super saturated.

Types of Aqueous Solutions Concept 2

Now here we're going to talk about the different types of aqueous solutions. Now, depending on the amount of solute added to our solvent, our solutions can either be saturated, unsaturated or super saturated. Now when we talk about the type of solution, we're going to say that our saturated solution is a stable solution as well as our unsaturated solution. The Super saturated solution itself though is unstable.

Now the amount of dissolved solute in each. When we're talking about a saturated solution, that means we've reached our maximum amount of solute that's been dissolved. For our unsaturated, we say we haven't reached our maximum amount of potentially dissolved solute, so that means additional solute can be dissolved. And then when it comes to our supersaturated solution, we're going to say super means greater than normal. So we've gone beyond our Max. We've gone beyond our maximum amount of solute that can be dissolved.

What effect does this have on our equilibrium concentration? Well, here if you're a saturated solution, we've reached our maximum amount of dissolved solute, so we've reached an equilibrium concentration. Now here when you're unsaturated, you can further dissolve more solute because you haven't reached your equilibrium amount, so you're less than the equilibrium concentration. And then finally for super saturated we've gone beyond our Max, so that means we're going to have more than our equilibrium concentration.

Now if we want to think about this in terms of visually, in terms of solid being added. So let's say we have 100 M LS of water. This hundred MLS of water can dissolve at Max 20 grams of solute. So if I took those 20 grams of solute, all of them would be dissolved. And here are water has changed into this purple solution to show that it's a saturated solution. Now again, we still have the 100 MLS of water. Remember, its maximum amount that it can dissolve is 20 grams of solute.

Here we're not dissolving 20 grams anymore, we're only dissolving 15g. So it's not as purple as our saturated solution because there's still room to dissolve an additional 5 grams of solute. And then finally, here we have our supersaturated solution. Here it can dissolve 20 grams Max of solute unless I do things to force it to dissolve an additional amount. Here one of the things that we can do is increase in the temperature. By increasing the temperature I can go beyond my 20 grams of solute and in this case I'm successfully able to dissolve 23 grams of solute.

I've gone 3G over my maximum. I am beyond my Max amount of solute dissolved and you can see as a result of this, the solution is even more purple because it's gone beyond its equilibrium concentration, right? So just remember a saturated and unsaturated solution are both stable. They happen normally. A super saturated solution is not a stable solution, so it needs additional help. Adding heat is a good way of forcing a super saturated solution to be formed all right, so keep this in mind when comparing these three different types of solutions.

Types of Aqueous Solutions Example 1

Here we're told that the solubility of a substance is 56g per 100 mL of water at 20�C. So basically we can dissolve up to 56 grams within 100 mL of water at that temperature. Now here we're saying a solution of this substance is prepared by dissolving 80 grams in 100 mL of water at 75�C. The solution is then slowly cooled slowly at 20�C without any solid forming.

The solution is all right, so we're at a higher temperature, so heat has been applied to it, allowing our solution to dissolve more than the 56 grams it normally can. Here it's dissolving 80 grams. They're telling us that we're cooling it back down at 20�C, and nothing recrystallizes. That means we have still 80 grams dissolved as we cool down to 20�C. So we're still dissolving more than our maximum amount, our maximum equilibrium amount, and because of that, because we've gone beyond our Max, we are a super saturated solution.

So here we'd say C is the correct answer. We've gone beyond our 56 grams that we normally would dissolve at 20�C. Of course it makes sense that we go beyond that 56g at a higher temperature. What's most important is when I get back down to 20�C, am I still dissolving that extra amount? If I am, then I'm a super saturated solution, so here option C would be the best answer.

D doesn't work because let's take it back down to 20�C and see if any recrystallization has occurred. That's when we know for sure we have a super saturated solution. Here. These answers don't work either.

The solubility of KClO₃ in water at 30ºC is 10 g per 100 mL of water. A 0.95 M solution of KClO₃ in water at 30ºC is:

• A. saturated
• B. supersaturated
• C. unsaturated

Here’s what students ask on this topic:

Which aqueous solution has the lowest freezing point?

To determine which aqueous solution has the lowest freezing point, we need to consider the colligative properties of solutions, specifically freezing point depression. The freezing point of a solution is lower than that of the pure solvent because the presence of solute particles disrupts the formation of the solid phase. The extent of freezing point depression is directly proportional to the molality of the solute particles in the solution.

For non-electrolytes, the solution with the highest molality (moles of solute per kilogram of solvent) will have the lowest freezing point. However, for electrolytes, which dissociate into ions in solution, the van't Hoff factor (i), which represents the number of particles the compound dissociates into, must be considered. The effective molality is then the product of the molality and the van't Hoff factor.

Therefore, an aqueous solution of an electrolyte with a high van't Hoff factor and high molality will have the lowest freezing point. For example, a 1 m CaCl₂ solution, which dissociates into three ions (i = 3), will have a lower freezing point than a 1 m glucose solution (i = 1), assuming equal concentrations.

What is an aqueous solution?

An aqueous solution is a solution in which water is the solvent. A solvent is a substance that dissolves a solute, resulting in a solution. In the context of an aqueous solution, the solute can be a solid, liquid, or gas that is dissolved by the water. When the solute dissolves, its individual atoms, ions, or molecules get surrounded by water molecules. The resulting homogeneous mixture is what we refer to as an aqueous solution.

These solutions are fundamental in chemistry, biology, and a variety of scientific and industrial applications. For example, when table salt (sodium chloride) is added to water, it dissociates into sodium and chloride ions, creating an aqueous solution. The ability of water to dissolve so many substances is due to its polar nature, which allows it to form hydrogen bonds with different solutes, facilitating their dissolution.