Conjugate Acid/Base Pairs Quiz - By beachybum28
Start studying Chemistry Quiz Acids and Bases. What are conjugate bases and acids and how do they relate to their Strong Acid - Weak Conjugate base What is the relationship between strength of acid/ base in neutralization?. We will cover acid and base definitions, pH, acid-base equilibria, acid-base Conjugate acid-base pairs. (Opens a modal) · Relationship between Ka and Kb. Play this game to review Acids & Bases. What is the conjugate base in the following reaction?.
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.
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. 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.
Conjugate acid-base pairs (video) | Khan Academy
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.
Acids and bases | Chemistry | Science | Khan Academy
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.
So let's look at some more examples of conjugate acid-base pairs. We saw above, HF, or hydrofluoric acid, it's conjugate base is F minus.
Acids and bases
So here HF is our acid, and when it loses that proton, we are left with F minus. We saw in the same reaction that water can act as a base.
So if water is our A minus, if that water accepts a proton, it forms the conjugate acid H3O plus. A Brief Review, see also pp and pp H has one proton, one electron, and no neutrons. HCl donates a proton to water.
Therefore, HCl is an acid. H2O accepts a proton from HCl. Therefore, H2O is a base. Water can behave as either an acid or a base.
Amphoteric substances can behave as acids and bases. Similarly, whatever remains of the base after it accepts a proton is called a conjugate acid. Consider After HA acid loses its proton it is converted into A- base. Therefore HA and A- are conjugate acid-base pairs. Conjugate acid-base pairs differ by only one proton. OH- is the strongest base that can exist in equilibrium in aqueous solution. The conjugate base of a strong acid e.
Cl- has negligible acid-base properties. Similarly, the conjugate acid of a strong base has negligible acid-base properties. The higher the pH, the lower the pOH, the more basic the solution.
Chapter 17: Multiple choice questions
Most pH and pOH values fall between 0 and There are no theoretical limits on the values of pH or pOH. However, certain dyes change color as pH changes. Indicators are less precise than pH meters. Many indicators do not have a sharp color change as a function of pH. Most indicators tend to be red in more acidic solutions two exceptions: Strong acids are strong electrolytes.
All strong acids ionize completely in solution: If the molarity of the acid is less than M then the autoionization of water needs to be taken into account.
- Quiz number 5 will be given in recitation next week, Feb 26-Mar 2
- Conjugate acid-base pairs
Therefore, the pH of the solution is the initial molarity of the acid. Strong Bases Most ionic hydroxides are strong bases e. The pOH and hence pH of a strong base is given by the initial molarity of the base. Be careful of stoichiometry. In order for a hydroxide to be a base, it must be soluble. Bases do not have to contain the OH- ion: There is a mixture of ions and unionized acid in solution. Therefore, weak acids are in equilibrium: H2O is a pure liquid.
The larger the Ka the stronger the acid i. Using Ka to Calculate pH Weak acids are simply equilibrium calculations.