In this example, it says, write a plausible mechanism for the following esterification reaction. So if we take a look here, we have this carboxylic acid and this alcohol which together interact to make this ester group. We have this acidic carboxylic acid that is ortho to it which is helping to enhance this process in a current. So step 1 has to do with protonation and nucleophilic attack. We're going to say the carbonyl group is protonated through intramolecular protonation.

And we're going to say the methyl methanol molecule attacks the protonated carbonyl group. Alright. So what's gonna happen here is this double bond breaks and goes to the oxygen which causes this lone pair to grab this hydrogen and the bond breaks to this oxygen. So this oxygen here will be negative. This group here becomes an OH group.

Our methanol group is also attacking here causing this whole breakage. So that we're going to add it here. There goes the methanol. Oxygen is making 3 bonds so it's positively charged. And then the OH was there originally, this one is still there.

So we create this structure. Step 2 now is proton transfer. We're going to say H⁺ is transferred from the methoxy oxygen to the hydroxy oxygen. So if we take a look here, here's our structure.

We're going to say that this H here can be transferred to this OH here. That's going to create a water molecule here. Oxygen is making 3 bonds so it's positive. And then this oxygen finally becomes neutral. So remember water is a good leaving group.

So last step, step 3 is leaving group and proton transfer. So the carbonyl group is reformed and water is kicked out. What's going to happen here is this comes here to remake a double bond kicking out this water molecule. So here we have a protonated carbonyl oxygen group. So the final product is formed after an intermolecular proton transfer.

So we have this negative oxygen. We have this positive oxygen. We're going to have this hydrogen transferring over to this negative oxygen making it neutral. So what we're going to get at the end is this. Here goes our carboxylic acid reconstituted and then we have this portion here with our carbonyl oxygen.

So this will represent the process when we're talking about the esterification of our starting carboxylic acid with this methanol molecule. This is the process that would happen. And this acidic carboxylic acid group is helping to have this happen. Okay. So it's helping to basically catalyze this reaction so that we can get to this ester product at the end.