Sign up for free to keep watching this solution

Solution: Which equation corresponds to the overall reaction for which...


Which equation corresponds to the overall reaction for which steps 1 and 2 describe the mechanism? 

Video Transcript

Hey everyone. So, here's our reaction, I went ahead and drew it out for you. Now, I didn't include some of the methyl groups, so that maybe it looks a little bit easier for you to understand, but basically what's going on is we have a two-step reaction that's an elimination reaction, we're reacting our tert-butyl bromide with our ethanol to get 2-methyl propane and it gives us our energy diagram, okay? So we're going to be dealing with this for the next couple of questions, so if we scroll down the first question that we're dealing with looks like this, and I'm going to jump out of the page really quick. So, here what you see is 4 different reactions and our question states, which one of these best represents our reaction, okay? So this is just going to be a little bit of a summary, if we scroll up what we see is we get our double bond is our product and then we get this protonated ethanol, okay? So, all we need to do is look for that in our final answer, so if we scroll down we see that here we get the double bond and we get it at all of these places, okay? that 2-methyl propane but let's take a look at which reaction is the correct one, which one do you think it is? well, remember that is HBr one of our byproducts if we look at A, is this one of our byproducts? Well, if we scroll up it looks like it's not, right? Because the only by-product we're getting in our first step would be this Br minus, this bromide ion, but then remember what happens in our next step is if we look at this ethanol it's going to have these double, these lone pairs on it, excuse me, it's going to come in and grab one of these hydrogens here and when it does that we're going to get an elimination, so we expect that ethanol to be protonated, so that's where that hydrogen is going to go to, it's going to go right here, okay? So, this reaction, this mechanism here in Cm this summary of our equation is the only correct one, okay? All the other ones are incorrect. Notice that in B what we have then we still have that ethanol as a byproduct and HBr we know that's incorrect, we can cross out B, we already said why A is incorrect and if we look at D we just see we have this proton right here, okay? We form our carbocation, which we also will do in step C but this is just a summary remember, so it's not showing you actually all the steps. Alright guys, so I really hope this made sense, so now let's take a look at your next problem.