 OK, so let's try this reaction. So this was, it said, how do we prepare diethyl ether industrially using ethanol, water, and sulfuric acid? OK, so let's write the mechanism for that reaction. Remember, when we're writing mechanisms, we want to kind of expand these structures. And remember, whenever we have water or any sort of alcohol or something and sulfuric acid or any strong acid, strong acid's going to react with that water first. OK, so let's show that step over on the side. Acid, strong enough base. Be proud of me. Check your PKs if you need to remind yourself about this reaction. So this is the active catalyst for this reaction. What I'm going to do here is, of course, deprotonate. So strong acid, again. We're going to have the Bronson base there. What are we going to make when we do that? And again, this is going to be an equilibrium, so I might as well show them. The H2O is reformed now. Not important anymore in the reaction. The next thing is you're going to have another one of these ethanol molecules. So remember, this is like an ocean of ethanol. It's not just one ethanol molecule. So you can have another ethanol molecule come in and react with the first one, and that's what's going to happen here. And if you look, so we've got our oxonium ion here. That's the oxygens attached to a primary carbon. So we've got another ethanol molecule going to react with this thing. It's going to be an SN2 reaction, because the water is not going to leak by itself. Because of course you would have to then make the primary carbon count, which is 8. OK? So in order to do the SN2 reaction, we have to drop another ethanol molecule. And in fact, let's get this other stuff out of here, so we won't confuse this. Is everybody OK with me erasing the sulfuric acid and water reaction up here? The lone pair sees that electrophilic carbon there. So backside attack SN2. It's going to hit it, knock off the staple water molecule there, so good leaving group, right? And that's going to be your forward arrow. So that's what's dragging the reaction there. So what are we going to get? Like that. Plus a water molecule, and I'll draw that out. So I'm going to use that as my base to regenerate my active catalyst. So hopefully, everybody can see, this is just the protonated version of diapoleether, or the conjugate acid of diapoleether, right? Do you see that? Yes. On your bowl. So we're going to now, do you protonate? Like that. As you might have imagined, this one's also an equilibrium. But we'll just write the power down. There's your diapoleether, and your H3O plus. That can go and make another protonated alcohol, protonated ethanol, and start the process all over. And your final diapolefetionate solution, OK? Pretty obvious mechanism, right? OK, so if you're having a hard time doing that, I would suggest you draw it, and draw it, and draw it, and draw it, and tell you to learn it. OK?