What is the conjugate acid-base relationship of (H2PO4)- and (HPO4)-? | Socratic
After losing a proton, the acid species becomes the conjugate base. If so, what is the relationship between Ka of the conjugate acid and Kb of the but understanding what problems require this type of conversion is difficult. It's just a relationship between a base and whatever happens to it if you add a proton, or an acid and whatever happens to it if you remove a. (a) What is the conjugate base of each of the following acids: HClO4, H2S, PH4 .. to the equilibrium problems we encountered in Chapter We can .. constants for HF and NH3, and use the relationship between Ka and Kb to calculate the.
Strong bases react quantitatively with water to form the OH- ion. Once this happens, the solution cannot become any more basic.
Acids and Bases - Conjugate Pairs
The Advantages of the Brnsted Definition The Brnsted definition of acids and bases offers many advantages over the Arrhenius and operational definitions. It expands the list of potential acids to include positive and negative ions, as well as neutral molecules. It expands the list of bases to include any molecule or ion with at least one pair of nonbonding valence electrons.
It explains the role of water in acid-base reactions: It can be expanded to include solvents other than water and reactions that occur in the gas or solid phases. It links acids and bases into conjugate acid-base pairs. It can explain the relationship between the strengths of an acid and its conjugate base.
It can explain differences in the relative strengths of a pair of acids or a pair of bases. It can explain the leveling effect of water the fact that strong acids and bases all have the same strength when dissolved in water. And then we can look at that same process happening in the backwards reaction. So if we look at the backwards reaction, which is also happening, the fluoride ion can pick up or accept a proton from somewhere. So it can pick up an H plus, so I'll have a plus, H plus here. And so when fluoride accepts a proton, we reform our HF.
So we can see that HF and F minus have this special relationship where you can form one or the other by losing or gaining a proton. And we can see a similar relationship between water and hydronium. So, water here, we said water is accepting a proton from HF, so we see that water will gain a proton, and that will give us hydronium.
Conjugate Acids of Bases - Ka Kb and Kw
In the reverse reaction, hydronium can lose a proton to reform water. So, minus H plus. So again we have these two species, water and hydronium, that are related to each other by having, or not having, one H plus.
So in chemistry, we call these species that are related in this way conjugate acid-base pairs. So the official definition, or my official definition of a conjugate acid-base pair is when you have two species that are related to each other. Let's see, two species that are related to each other, related by one H plus. In this case, we have HF and F minus that are related to each other by that one H plus.
And so HF and F minus are a conjugate acid-base pair. We also have water and hydronium, which are also related by that one H plus.
Acid-Base Pairs, Strength of Acids and Bases, and pH
So water and H3O plus are also a conjugate acid-base pair. You can probably tell from the name, but whenever you have a conjugate acid-base pair, one thing in the pair will be an acid, and the other thing will always be a base. The definition of which one is the acid and which one is the base comes from the Bronsted-Lowry definition of acids and bases. So the Brondsted-Lowry definition says anything that can donate an H plus, so anything that will give away an H plus is an acid.
So we can see that, in this case, our hydrofluoric acid is acting as the acid in the conjugate acid-base pair. And that means that fluoride has to be acting as the base. And that makes sense, because the Bronsted-Lowry definition of a base is something that will accept an H plus.
And that's exactly what it does in the reverse reaction. Your F minus will pick up an H plus and go back to your acid.
Conjugate acids and bases - Chemistry Stack Exchange
So we can also look at water and H3O plus. So here, water is gaining a proton, or accepting it, so water is acting as a base. And in the reverse reaction, H3O plus is donating a proton, so H3O plus is acting as an acid. The relationship between conjugate acid-base pairs we can write a little bit more generally.
So, if we represent any generic acid as HA. So this is our acid. We said that a acid is something that donates a proton.
So it'll lose the proton, and when it does that, it will form the conjugate base, which is represented by A minus. In the reverse reaction, our base, A minus, can gain a proton and remake our acid, or conjugate acid. So whenever you have two species that have basically the same formula, which we abbreviated here as A minus, except for one has an H plus and one doesn't, then you know you have a conjugate acid-base pair.