Electrolytes (Simplified): Study with Video Lessons, Practice Problems & Examples

Electrolytes are compounds that conduct electricity when dissolved or melted, categorized into strong, weak, and nonelectrolytes. Strong electrolytes, like sodium chloride, fully dissociate into ions, enhancing conductivity. Weak electrolytes, such as hydrofluoric acid, partially dissociate, resulting in limited ion formation and conductivity. Nonelectrolytes, like glucose, do not dissociate into ions and therefore do not conduct electricity. Understanding these distinctions is crucial for grasping concepts in acid-base chemistry and solution properties.

Electrolytes (Simplified) Concept 1

Electrolytes represent compounds that conduct electricity when entering their ionic forms when dissolved or melted. 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 in solid form. When placed in water, it breaks up completely into its 2 ions, which are sodium ion aqueous, plus chloride ion aqueous. Remember, the aqueous just means that water is surrounding that particular ion. And remember also that we're going to make 100% of both of these ions. 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. And there are a lot of different strong acids. These are the most important ones that you keep in mind. We have hydro, hydrobromic acid, hydrochloric acid, hydroiodic acid, nitric acid, perchloric acid, and sulfuric acid. Strong bases, strong bases we have sodium hydroxide, potassium hydroxide, lithium hydroxides. These are some basic examples of strong bases. We'll go into greater detail in terms of other strong bases for now, but 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. So here we're going to have iron(III) nitrate as a solid. It's 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 3 (NO 3 ) 3 (s) → Fe 3 + (aq) + 3 NO 3 − (aq)

Electrolytes (Simplified) Concept 2

Now, weak electrolytes represent solutes that partially dissolve. 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 in 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 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. Your weak electrolytes 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 a HF aqueous, and very little 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 is weak. Weak because we don't make very many of those ions on the product side. Here we have, in green, our insoluble ionic compounds like 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) 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 being surrounded by water, so you can still say it's aqueous. Now examples of other non-electrolytes include water, sugars like glucose, and 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 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 alcohol 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? Now, their degree of dissociation is: 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 nonelectrolyte. Here we have an alcohol in the case of methanol. We also have these other structures here. We have water, hydrogen peroxide. We also have CH₄N₂O, which is just an example of a molecular or covalent compound. 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, that means 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. So 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. So this one is weakly electrolytic. And non-electrolytic, none of these ions would form and they would all exist in this molecular form here, and that would be the first one. So the first one will 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 the same form. So, this would mean that it has to be a non-electrolyte. So, 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 here mercury liquid becoming mercury aqueous, 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) in water dissociates into Na⁺ and Cl⁻ ions. These ions are free to move in the solution, allowing the solution to conduct electricity efficiently. Strong electrolytes include soluble ionic compounds (like NaCl, KBr), strong acids (such as HCl, HNO₃), and strong bases (like NaOH, KOH). The presence of a high concentration of ions in the solution is what makes strong electrolytes excellent 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 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) in water dissociates into H⁺ and F⁻ ions, but most of the HF remains undissociated. This limited ion formation results in weak electrolytes conducting electricity poorly compared to strong electrolytes. Weak electrolytes include weak acids (like HF, CH₃COOH) and weak bases (such as NH₃, Mg(OH)₂). The key difference is the degree of dissociation: strong electrolytes dissociate completely, while weak electrolytes do so only partially.

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 the solution, which means they cannot conduct electricity. A common example of a nonelectrolyte is glucose (C₆H₁₂O₆). When glucose dissolves in water, it remains as intact glucose molecules surrounded by water molecules. Other examples include sucrose (C₁₂H₂₂O₁₁), methanol (CH₃OH), and water (H₂O). Since nonelectrolytes do not produce ions, they lack the charged particles necessary to carry an electric current, making them non-conductive.

How can you identify a strong electrolyte in a chemical equation?

To identify a strong electrolyte in a chemical equation, look for compounds that completely dissociate into ions in solution. These are typically represented by a single arrow (→) indicating complete dissociation. For example, NaCl (sodium chloride) in water is written as NaCl → Na⁺ + Cl⁻. Strong electrolytes include soluble ionic compounds, strong acids (like HCl, H₂SO₄), and strong bases (such as NaOH, KOH). The presence of a single arrow and the complete dissociation into ions are key indicators of a strong electrolyte.

What are some examples of weak acids and weak bases?

Weak acids and weak bases are compounds that only partially dissociate into ions in solution. Examples of weak acids include hydrofluoric acid (HF) and acetic acid (CH₃COOH). These acids do not fully ionize in water, resulting in a mixture of ions and undissociated molecules. Examples of weak bases include ammonia (NH₃) and magnesium hydroxide (Mg(OH)₂). These bases also partially ionize in water, producing fewer ions compared to strong bases. The partial dissociation of weak acids and bases results in limited conductivity in solution.