Bronsted Lowry Acid and Base - Video Tutorials & Practice Problems
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In 1923, Johannes Brønsted and Thomas Lowry developed a new set of definitions for acids and bases.
Understanding Bronsted-Lowry Acids and Bases
According to Brønsted and Lowry, an acid was classified as a proton donor while a base was a proton acceptor.
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concept
Bronsted Lowry Acids & Bases Concept 1
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Hey, guys, In this new video, we're gonna take a look at another type of acids and bases and probably the most important of the three Bronston Laurie. So here we're gonna say it was in 1923 when Bronston and Laurie developed a new definition for acids and bases. Iranians devised Arrhenius acids and bases near the end of the hundreds. And it was in the new century 1923 where these two guys helped to make that definition a little bit better, we're gonna say, according to their definition and acid was considered to be a Proton donor. And when we say proton, we mean h plus. So this first definition still goes in hand with the Iranians definition because the Iranian acid is something that increases H plus concentration when dissolved in water, Bronston Laurie still agreed with that. They said that we agreed and acid should have an H plus where they disagreed though Bronston or didn't believe that a base needed an O. H. Minus to be a base, what they said instead, waas. If the acid donates h plus, then the base must accept the H plus, so their new definition for a base. Waas bases are proton, which means H plus except er's. So this is where they differed from Arrhenius. So what we're gonna say here is we're gonna say, unlike acids and bases for radius these we could use in solutions that we're not just made up of water and we're gonna stay here. Arrhenius assets say their H plus um, they increase h plus brassell. Laurie says they give h plus, so both agree. So you can say that Arrhenius acids are Bronston Laurie acids. Now, we're also gonna say here that according to Bronston Laurie, a base except H plus why would a base except H plus because it has lone pairs or it has a negative charge? Something positives of something negative naturally are attracted to one another. This kind of goes in line with Arrhenius a little bit because, according to Iranian, we have to produce O. H minus H minus is negative. So it could except h plus. So there's a little bit of disagreement, but also a little bit of agreement in terms of basis. Now we're gonna say that Bronston Laurie acids and bases are always occurring in pairs, which we call conjugate acid base pairs. And what you need to remember is that conjugate acid base pairs differ by only one hydrogen. So a good example is we have ht. Well, we could have o h minus. We could have a three plus here. These two are conjugate acid base pairs. They're only different by one H water has to h is o H minus. Only has one. And you're gonna say that these two could be conjugate acid base pairs as well. H 30 plus has three h is h 20 has to their Onley different by one h plus. So that's what we mean by conjugate acid base pairs.
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example
Bronsted Lowry Acids & Bases Example 1
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Now let's take a look at example one, it says right. The formula of the conjugate base for the following compound. Now, the following compound is H s 04 negative and realize when I say conjugate base, I mean remove and h plus. And since we're gonna be using some of the spaces here, guys to write graphs to help us follow along, I'm gonna remove myself from the image so we can better focus. So remember, conjugate base means were removed h plus, So just do a number line. This number line will help us figure out what the new charge is going to be. Because, remember, you're not only moving and h you're moving Ah, positive h. So you're causing the charge to change when that h positive comes off. So it's important to track and see what your new charge will be. So we start off as negative one. And if you're removing an H positive, you're removing a positive, you're gonna become more negative. Yeah, So let's remove that H plus. So now we're s +04 because we're gonna become a little bit more negative. We fall down to minus two. So s 04 to negative would be the conjugate base off H s 04 negative
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Bronsted Lowry Acids & Bases Example 2
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for example, to we're doing the complete opposite. Now we're looking for a conjugate assets, so that means ad and h plus. Remember, adding a positive to you makes you more positive. So you become mawr Positive number line again. Okay, so let's add an H to it, so it becomes HV 205 Just add the H to the front of the compound. That's all you have to do. Not to the center to the side Here was negative. Two. When I add an H plus, it becomes more positive, so it jumps up to negative one. So our compound now is V H V 205 minus one. Now that you guys have seen how to do conjugate acids and bases, I want you guys to attempt to do practice. Question one and practice question, too. Good luck.
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Problem
Problem
Write the formula of the conjugate base for the following compound:
H2Se
A
B
C
D
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Problem
Problem
Write the formula of the conjugate for the following compound:
NH2NH2
A
B
C
D
Brønsted – Lowry Reactions
Brønsted – Lowry acid and base reactions create products that are conjugates of the reactants.
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example
Bronsted Lowry Acids & Bases Example 3
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Hey, guys, In this new video, we're gonna put to practice some of the concepts we learned about Bronston, Laurie acids and bases. So let's take a look at the first example here. It says identify the acid, the base, the conjugate acid and the conjugate base based in the following reactions. So here we have HF acquis plus H +20 acquis, which gives us f minus acquis plus h +30 plus. So remember, what does a Bronston Laurie acid do? It gives away h plus. Ah, Bronstein Laurie based on the other hand, will accept that h plus. So if we take a look here we have HF but then look what happens to the h f. It becomes f minus. What must have happened that HF gave away an H plus to the water because it gave its H plus away. It's the acid. The water, on the other hand, accepted that h plus, that's how it became a three plus over here. So here, this must be the base. Then we're gonna say HF gives away an H plus to become F minus. Since we're taking away an H plus, this must be the conjugate base H 20 accepts an H plus to give us a check. +30 plus So H +30 plus must be the conjugate acid. We're gonna say that these two are connected together as our conjugate acid base pair. And then these two are connected together as our other set of conjugate acid base pairs. Remember, we talked about this earlier The only differ by one hydrogen if they're different by one h their congregants of each other.
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example
Bronsted Lowry Acids & Bases Example 4
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now that we've done that one. Let's take a look, at example, too. An example to we have to do the same thing once again. So here we have seeing negative, but all of a sudden it becomes H. C n. How did that happen? The C N must have accepted in H plus because it's accepting the H plus. It's a base. Who's giving it that h plus? It must have been the water water gives away an H plus, making it an acid. When water gives away the H plus, what happens to the water? The water becomes O H minus. So here we would say that this is the conjugate base. Whatever you are, you're conjugate is the opposite. So if this is a base, this is a conjugate acid. And then, based on that, we'd say that these two, our congregants of one another and then these two also and just realize water acts as a base in the first example. But as an acid in the second, something that can act as an acid or base, we said, was called AMFA Terek. So water is the best example of an AMFA Terek species, depending on what it's next to, it could act as either an acid or base. It's always be careful and we know that this has to be the base because it's negative. We're still using the rules we've learned before. And if we go back upto water, actually how do we know H f is the acid in H 20 is the base Because, remember, they're both going to have HK connected toe on electoral negative element. F and O are both in the same period. Remember we said when you're in the same period, what do we look at? We look at electoral negativity, so HF is definitely a stronger acid than H 20 As a result, HF must be the acid H 20 must be the base. So the rules we learned earlier play a huge role in what we're doing right now. Here I gave us the product. So is easy to say who was the acid and who was the base. But on your exam, you may not get that luxury. Your professor might just give you HF plus water and ask you what is what are your products. So you still have to remember who would be the stronger acid. That person will be the acid who the other would have to be the base. Now that we've seen that, let's take a look at practice questions one and two. So for this one, we're asking which of the following is a Bronston Laurie acid, So I'll give you guys a huge help here. Remember, Bronson Laurie Acid has to have h positive in there. Has to have a check if it doesn't have agents out. Second for something to give away an H H needs to be connected, so something that is electoral negative. So if age is connected to an electro negative element, it's gonna make a polar bond. If that bond is polar, that means it's reactive. That means I can break it and take that age plus off what bonds or not polar. While if H was connected to itself, this would be a non polar bond. So as a result, H two does not represent an acid. Also, who else? We could also say that h, when it's connected to see their electoral negativity, are not that far off from one another. So they're electro negativity. They're very similar so we would expect that bond not to be polar. So as a result, if you have h connected to carbon, we would expect that to not be an acidic bond. So I gave you guys to huge helps to help you figure out which one of these could be a Bronston Laurie acid. Use the rules that we've learned earlier to identify something as either an acid or base that will help guide you to what's a Bronston Laurie acid for this particular question?
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Problem
Problem
Which of the following is a Bronsted-Lowry acid?
A
CH4
B
HCN
C
NH3
D
Br2
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Problem
Problem
Determine the chemical equation that would result when carbonate, CO32-, reacts with water.
A
B
C
D
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