Electrolytes (Simplified) - Online Tutor, Practice Problems & Exam Prep

Electrolytes are compounds that conduct electricity in ionic form when dissolved. Strong electrolytes, like sodium chloride, fully dissociate into ions, enhancing conductivity. Weak electrolytes, such as hydrofluoric acid, partially dissociate, resulting in fewer ions and lower conductivity. Nonelectrolytes, like glucose, do not dissociate into ions and cannot conduct electricity. Understanding these distinctions is crucial for grasping concepts in acid-base reactions and solubility rules, which are foundational in chemistry.

Electrolytes (Simplified) Concept 1

Electrolytes represent compounds that conduct electricity when they enter their ionic forms when dissolved or melted. Now recall that conductivity is a physical property that deals with the ability of an electrical current to flow through a material. If we're going to talk about different types of electrolytes, let's start with the strong ones. They represent solutes that completely dissociate into ions when placed in a solvent, typically water. A great example of a strong electrolyte is sodium chloride (solid). When it is placed in water, it breaks up completely into its two ions, which are sodium ion (aqueous) plus chloride ion (aqueous). Remember, 'aqueous' just means that water is surrounding that particular ion. And just remember also that 100% of both of these ions are made. Strong electrolytes can represent aqueous soluble ionic compounds, which we learned through the solubility rules, strong acids, as well as strong bases.

Now let's look at classifications of this type of electrolyte. The type of electrolyte, of course, is strong. Its degree of dissociation, we're going to say that it completely dissociates, so it breaks up 100%. Because of this, what are the species in solution? Well, the solid form no longer exists. It's been entirely converted into ions. And then conductivity, yes. Because it breaks up into ions, those ions can conduct electricity. Great examples of soluble ionic compounds would be sodium chloride, sodium nitrate, potassium bromide, magnesium chloride. These are based on our understanding of the solubility rules. So, if you haven't watched my videos in terms of them, I highly suggest you go back and take a look.

Next are strong acids. There are a lot of different strong acids. These are the most important ones that you should keep in mind. We have hydrobromic acid, hydrochloric acid, hydroiodic acid, nitric acid, perchloric acid, and sulfuric acid. Strong bases include sodium hydroxide, potassium hydroxide, and lithium hydroxide. These are some basic examples of strong bases. We'll go into greater detail in terms of other strong bases for now, but here these are three great examples. So just remember, strong electrolytes break up completely into ions and therefore those ions are good conductors of electricity.

Electrolytes (Simplified) Example 1

Write a balanced equation for the dissociation of the following strong electrolyte in water. So here we have iron(III) nitrate. We will have iron(III) nitrate as a solid. It is going to break up in water. Since it's a strong electrolyte, we have a solid arrow going forward. It breaks up into our iron(III) ion, aqueous, plus 3 Nitrate ions, aqueous. This here would represent the balanced equation for this particular strong electrolyte.

Fe(NO 3 3 → Fe ⁺ 3 + 3 NO 3 ⁻ 1

Electrolytes (Simplified) Concept 2

Now, weak electrolytes represent solutes that partially dissolve. So they partially dissolve into ions when placed in a solvent. Here we have HF. HF is hydrofluoric acid, which is a weak acid. Acids are typically found in their aqueous form and solution. Here, it's going to break up into the H⁺ ion aqueous plus F^- ion aqueous. Realize here that we see a double arrow here, this reversible arrow. This indicates that we have a weak electrolyte. So if you're ever looking at a balanced equation and you see a double arrow or reversible arrow like this, that means that this is a weak electrolyte. Now, weak electrolytes can be either insoluble ionic compounds. Yes. Even insoluble ionic compounds break up a little bit. Weak acids or weak bases. So here, let's take a look at the classifications of electrolytes. We already went over the ramifications of electrolytes. We already went over the strong electrolytes earlier. If you haven't looked at that video, make sure you go back and take a look. Now let's look at your weak electrolyte. So your weak electrolytes, they don't dissociate completely, they dissociate partially. Because they only partially dissociate, it's mostly molecules and only some ions. So if we look up above, we would say that for this weak electrolyte of hydrofluoric acid, a vast majority of it would stay in this form of HF aqueous, and very little bit of these ions would actually be formed. So a vast majority of it is still on the reactant side of the equation. Now conductivity, we're going to say weekly. Weekly because we don't make very many of those ions on the product side. So here we have in green are insoluble ionic compounds in calcium sulfate, barium sulfate, and calcium sulfide. These are just some examples of insoluble ionic compounds based on our understanding of the solubility rules. Great examples of weak acids are hydrofluoric acid, which we saw up above, and acetic acid. And then some great examples of weak bases are magnesium hydroxide and ammonia. Now, these are not the only weak acids or weak bases. These are just some great examples of weak acids and weak bases which we can classify as weak electrolytes. So just keep in mind the differences between strong electrolytes and weak electrolytes.

Electrolytes (Simplified) Example 2

Benzolic acid, which is C₆H₅COOH, is a weak acid. Would you expect the aqueous acid solution to contain it? Alright. So, it's a weak acid, so C₆H₅COOH. It is an acid, so it's aqueous. It is a weak acid, so it's a weak electrolyte, which means I have reversible arrows ↔⃗. It would produce these two particular ions, aqueous plus H⁺ aqueous. Now remember, because it's a weak electrolyte, it is mostly in its molecular form, its molecule form, and very few ions, so not many of these products would be formed. So we'd say here that it's mostly this compound here, very little of the ion. So, out of the choices, option C is the best one: mostly molecules for weak electrolytes with some ions formed.

Electrolytes (Simplified) Concept 3

So, nonelectrolytes consist of molecular or covalent compounds that don't dissociate into ions. Here we have a good example of glucose solid. Even after placing it in water, it doesn't break up. It's still altogether as glucose, but it's still surrounded by water, so you can still say it's aqueous. Now, examples of other non-electrolytes include water, sugars like glucose, alcohols, and other non-ionic compounds. Now, when I say sugars, sugars are just compounds with the molecular formula of C_nH_2nO_n. Okay? So, here for glucose, we saw C₆H₁₂O₆. Sucrose deviates a little bit from this. Sucrose is C₁₂H₂₂O₁₁. Glucose and sucrose are the most famous of the sugars that you'll most likely see when dealing with non-electrolytes. Alcohols are just covalent compounds with carbon and hydrogen connected to OH. Methanol is CH₃OH. Phenol is C₆H₅OH. A key thing to recognize in alcohols is that they end with the word 'ol'. Methanol, phenol. Now, we've talked about strong electrolytes. We've talked about weak electrolytes. But what about non-electrolytes? Their degree of dissociation is that they don't dissociate. So, we're going to say no dissociation. They don't break up into ions at all, so it's only molecules. And because they don't break up into ions at all, they don't conduct electricity. Sucrose is a great example besides glucose as being a non-electrolyte. Here we have an example with methanol, water, hydrogen peroxide, and CH₄N₂O, which are just examples of molecular or covalent compounds. So, just remember, non-electrolytes don't break up into ions whatsoever, and therefore, they cannot conduct electricity like strong and weak electrolytes can.

Electrolytes (Simplified) Example 3

The dissolution of a compound is given by the reaction below. Here we have a white sphere and a black sphere, and they break up into separate spheres, which represent their ions. Now identify each of the following solutions as either electrolytic, weakly electrolytic, or non-electrolytic. So if we take a look, something that's electrolytic is strong, meaning it would break up 100% into these ions. If we take a look here, the only one that shows us separate white spheres and black spheres where everything is completely broken apart is the last one. Therefore, this would be electrolytic. For the next one, we have weakly electrolytic and non-electrolytic. Weakly electrolytic would have more of these intact, but would also have some of these floating around as well. If we take a look, that would be the middle one. Hence, this one is weakly electrolytic. And non-electrolytic, none of these ions would form and they would all exist as this molecular form here, and that would be the first one. Hence, the first one would be non-electrolytic.

Each of the following reactions depicts a solute dissolving in water. Classify each solute as a strong electrolyte, a weak electrolyte or a non-electrolyte.

So here it says each of the foam reaction depicts a solute dissolving in water. Classify each solute as a strong electrolyte, a weak electrolyte, or a non-electrolyte. In the first one we have lead(II) sulfate and we have a solid arrow going forward. Here we don't see it breaking up into anything. It stays in its same form. So, this would mean that it has to be a non-electrolyte. Remember non-electrolytes do not break up at all into ions. For the next one, we have acetic acid. It's breaking up into ions here, but how do we know what kind of electrolyte it is? Well, look, we have reversible arrows or double-sided arrows. Remember that's indicative of a weak electrolyte. So here, this is a weak acid and therefore it is a weak electrolyte. That's why we have double-sided arrows or reversible arrows. For the next one, we have calcium sulfide. It is a solid arrow going forward, so it's not reversible and we see ions being formed. So this would have to be a strong electrolyte. Now finally, we have mercury liquid becoming mercury aqueous; it doesn't break up into ions, so this would also be a non-electrolyte. So these would be the classifications for each one of these reactions.

Which of the following represents a non-electrolyte? 

a) (CH₃)₂NH₂                             b) NaOH                       c) HIO₃                         d) C₂H₅OH                    e) CsNH₂

• A. (CH₃)₂NH₂
• B. NaOH
• C. HIO₃
• D. C₂H₅OH
• E. CsNH₂

Here’s what students ask on this topic:

What are strong electrolytes and how do they conduct electricity?

Strong electrolytes are compounds that completely dissociate into ions when dissolved in a solvent, typically water. This complete dissociation means that the solute breaks up 100% into its constituent ions. For example, sodium chloride (NaCl) dissociates into Na⁺ and Cl⁻ ions in water. Because these ions are free to move, they can conduct electricity efficiently. Strong electrolytes include soluble ionic compounds, strong acids like hydrochloric acid (HCl), and strong bases like sodium hydroxide (NaOH). The presence of a high concentration of ions in solution allows for the easy flow of electrical current, making these solutions good conductors of electricity.

What are weak electrolytes and how do they differ from strong electrolytes?

Weak electrolytes are compounds that only partially dissociate into ions when dissolved in a solvent. This partial dissociation means that only a small fraction of the solute exists as ions, while the majority remains as intact molecules. For example, hydrofluoric acid (HF) dissociates into H⁺ and F⁻ ions, but most of it remains as HF molecules. This results in fewer ions in solution, leading to lower electrical conductivity compared to strong electrolytes. Weak electrolytes include weak acids like acetic acid (CH₃COOH) and weak bases like ammonia (NH₃). The reversible nature of their dissociation is often indicated by a double arrow in chemical equations.

What are nonelectrolytes and why don't they conduct electricity?

Nonelectrolytes are compounds that do not dissociate into ions when dissolved in a solvent. As a result, they do not produce any ions in solution and cannot conduct electricity. Examples of nonelectrolytes include molecular compounds like glucose (C₆H₁₂O₆), sucrose (C₁₂H₂₂O₁₁), and alcohols like methanol (CH₃OH). These compounds remain intact as molecules in solution, and since there are no free ions to carry an electrical current, the solution remains non-conductive. Understanding the behavior of nonelectrolytes is important for distinguishing them from electrolytes in various chemical contexts.

How do solubility rules help in identifying strong electrolytes?

Solubility rules are guidelines that help predict whether an ionic compound will dissolve in water to form a solution. These rules are essential for identifying strong electrolytes because they indicate which compounds will fully dissociate into ions when dissolved. For example, compounds like sodium chloride (NaCl) and potassium nitrate (KNO₃) are soluble in water and thus act as strong electrolytes. By understanding and applying solubility rules, one can determine which ionic compounds will produce a high concentration of ions in solution, thereby enhancing electrical conductivity. This knowledge is crucial for studying reactions and properties of solutions in chemistry.

What are some common examples of strong acids and bases that are strong electrolytes?

Common examples of strong acids that are strong electrolytes include hydrochloric acid (HCl), hydrobromic acid (HBr), hydroiodic acid (HI), nitric acid (HNO₃), perchloric acid (HClO₄), and sulfuric acid (H₂SO₄). These acids completely dissociate into their respective ions in aqueous solution, making them excellent conductors of electricity. Similarly, strong bases like sodium hydroxide (NaOH), potassium hydroxide (KOH), and lithium hydroxide (LiOH) also fully dissociate into ions in water. The complete dissociation of these strong acids and bases results in a high concentration of ions, which facilitates the conduction of electrical current in solution.