Write equations for the following acid–base reactions. Label t...

Question

Write equations for the following acid–base reactions. Label the conjugate acids and bases, and show any inductive stabilization. Predict whether the equilibrium favors the reactants or products. Try to do this without using a table of pKa values, but if you need a hint, you can consult Appendix 4.
a. CH₃CH₂OH + CH₃NH⁻
b. F₃CCOONa + Br₃C—COOH
c. CH₃OH + H₂SO₄

a. CH₃CH₂OH + CH₃NH⁻

b. F₃CCOONa + Br₃C—COOH

c. CH₃OH + H₂SO₄

Accepted Answer

Hey everyone, let's solve this problem. It says consider the following acid based reactions, indicate the conjugate acids and bases in your answers and determine the direction of equilibrium. Try to determine reaction direction without the use of the P. K values. Well, instead of using the P. K values, we can determine the acidity using our acronym oreo, which stands for adam resonance inductive effect and orbital's. Right. So adam we're talking about the electro negativity of the atom that is holding the proton that is going to be given away. Right? So the more electro negative that adam, the stronger the acid and resonance, the more resonance the compound has, the stronger the acid, the more electro negative, the ab the atoms that are neighboring that depot donated atom than also the stronger the acid. So electro negative of neighbor neighbors and orbital's. We have S P orbital sp hybridization is the most acidic, then Sp two sp three. Okay, so let's draw these reactions. We have C L C H two C 00 H. That's a carb oxalic acid. So I know that's going to be my acid. It's pretty strong. And cl three cc 00 N A N A is sort of a spectator ion. So it's technically C 03 cc 00 minus. So that minus is a giveaway that it will be our base and this is our acid. So the conjugate it's will determine the direction in a second, C L ch two C O R asset is giving away the proton. So B C. 00 minus. But then we have that N. A. Spectator ion will go hang out there and then C. 03 cc. O. Now has an H. Right? We protein ated our base. So our acid, the conjugate base will be the opposite of our acid. Conjugate base in the conjugate acid is the opposite of our base. Right? So now we have to determine the direction of the equilibrium. Well we do that by determining which acid which side has the stronger acid. Okay so we're looking at this in this and we're not using P. K. Values but again we can look at Mario. So we're looking at where that hydrogen is attached to. So they're both attached to an oxygen. Okay. They also both have residents because they're both carb oxalic acids. But we can look at the inductive effect. Right? They both have chlorine atoms. But this congregate acid has three chlorine atoms. So this is going to be our stronger acid because it has a stronger inductive effect. Okay so this is our stronger acid. And what does that say about the direction of our equation or reaction? Rather well the reaction will favor the side opposite of the stronger acid. Right? Because that strong acid wants to donate the proton. So it's going to form that conjugate base. Right? Or the base rather on the other side that we labeled base. So it will favor the reactant here. Does that make sense. Alright Let's go into the next one Ch three Ch 20. H. And h. n. 0. 3. We'll leave it like this for now. So this is going to be my base and this is my acid. So let's draw the conjugate. It's so the conjugate acid of the base will now have an extra proton. Right? So that will be CH three CH Oh h. two. And that has a plus sign because this is neutral. Right? And oh no I didn't give myself in a room. Let me erase this. And we'll have N. 03 minus because we donated a proton. So this will be our conjugate acid and conjugate base. So which conjugate asset is stronger to determine the direction of our equilibrium. So we have H. N. 03. So the proton is attached to the nitrogen and the conjugate acid where the hydrogen is attached to that oxygen. Well there's a strong inductive effect from these three electro negative oxygen's. Whereas this has a bunch of hydrogen and carbons. So because of the stronger inductive effect on the H. N. 03, this will be our stronger acid. Okay. Which means our reaction will go favor the products right? It goes the opposite of the stronger acid because it wants to form those products. Right, okay. Last one we have CH 30. H. Methanol and H minus. We know hydrogen does not like to have a negative charge. So that is going to be our base with a negative charge. And this will be our acid and our asset will donate that proton CH three oh minus and H two will be happier with another hydrogen. So this will be our conjugate base, right? Because it's opposite the acid and H2 will be our conjugate acid opposite of the base. So which is a stronger acid CH 30. H. Or H. Two. Well that hydrogen here is just attached to another hydrogen, which is definitely not electro negative and the oxygen is electro negative. So this will be our stronger acid and sort of just knowing what we know generally about chemistry that hydrogen does not like to have that negative charge. I would much rather be here as a di atomic molecule. So you can kind of guess that this reaction will favor the products. But that just confirms or intuition. Right? All right, that's it for this problem. I hope this is helpful. And thanks for watching

Key Concepts

Acid-Base Reaction Mechanism

Conjugate Acid-Base Pairs

Inductive Effect and Stabilization

Watch next