Oxidizing and Reducing Agents - Video Tutorials & Practice Problems
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1
concept
General Features of Redox
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Hey, guys. Now I want to introduce the topic that you guys might have heard before from general chemistry, but in organic chemistry is going to be significantly different. And that topic is oxidation and reduction. So oxidation reduction. If you remember way back to Gen. Cam, you guys had to learn these complicated Redox equations where you had Thio do several steps to get the right numbers, and it was very quantitative. Okay, honestly, that was a part of general chemistry I didn't like very much. And that's part of why I'm tutoring or go, because I don't have to do as much math in organic chemistry. Oxygen reduction really boils down to. Are we adding oxygen's? Are we adding hydrogen? Okay. And instead of looking at these complicated formulas and equations, were really just gonna be able to look at the molecule itself to tell if it's going to be oxidized or reduced. So for those of you that might have struggled with that Injun Kem, this is your ticket to really succeed at oxidation reduction. So let's go ahead and look at the definitions really quick. So on oxidation reaction is really gonna be any reaction that involves the increase in the oxygen content of the molecule. All right, so you're increasing the oxygen content, you're increasing the oxidation. Now, one thing to keep in mind is that doesn't That doesn't mean that you're adding extra oxygen's. That just means that you have mawr carbons bonded to oxygen, all right, and you'll see how we can change that up in a second. There actually is a difference between the two. A reduction reaction would be any reaction that involves the increase of hydrogen content of a molecule. Okay, so as you're reducing something, you're increasing the amount of hydrogen is that it has. All right, so let's look at this little scheme. That is kind of a general roadmap of oxidation reduction. What you'll notice is that, first of all, oxidation and reduction are opposites of each other. That is something that even if you completely messed up with those equations in Gen. Cam, you should still no, they're opposites of each other. They're going in different directions. So let's go ahead and start off with probably the most reduced form or what is the most reduced form of carbon. And then we'll move forward. Okay, so the most. If I have to say one of these five structures is the most reduced structure, which one would it be? Would be the first one. Okay, that first structure is called methane K. As you guys can see, methane is the most reduced one Carbon hydrocarbon because it doesn't have any bonds toe oxygen. It has Onley bonds toe hydrogen. Okay, so methane would be fully reduced. Um, carbon. Now, as we start adding oxygen bonds, this is gonna progressively get mawr and more and more oxidized. Now, in this video, I don't want to focus on re agents. We'll do re agents in a little bit. But right now, I just want you Thio focus on how can I tell something's mawr oxidized or less oxidize something like that. So as we move in this direction as we went to the right in this little table here we're going to find is that you start having mawr and more and more bonds toe oxygen. So as you guys can see, a primary alcohol would be a little bit would be more oxidized than methane because that primary alcohol in the house one bond toe. Oh, okay. Now as we keep going, we can keep making more bonds to oxygen. So as you guys can see here, I have an alga hide. Right In this case, this is actually formaldehyde. That's the name of it, But I'll just keep it. Is Aldo hide? That's fine. And Alba hide is gonna be more oxidized than alcohol. Is it because it has more oxygen atoms? No, It's because the carbon has more bonds toe oxygen, so now has to bonds instead of one. That would be a more oxidized carbon. Let's keep going now I've got a car. Looks like acid, right? I'm just gonna write C o h. Remember that that is the condensed form of the functional group. So ah, car looks like acid would be even more oxidized because now you'll notice that as three bonds toe oxygen Finally, if I continue to keep oxidizing and oxidizing, notice that I'm getting rid of hydrogen and I'm adding wants oh, toe bonds to the oxygen. Finally, what I get to is fully oxidized carbon, which is actually considered in organic carbon. This is not an organic molecule. Why, because it has remembered the definition of organic molecules, was Ah, carbon bonded to ah, hydrogen. Okay, I'm sorry. I mean, needs carbon and hydrogen, but there needs to be hydrogen is present for it to be organic. So this would be inorganic because there's no hydrogen is present. This is CO two gas. Okay, So completely oxidized. Carbon actually just evolves as co two gas. Completely reduced carbon is methane gas. All right, so I just want you guys to get a general feel that we could go either way either direction on this chart, depending on what the region is. Okay. Now, the re agents that we're going to deal with in organic chemistry one are actually gonna be the ones that are in this gray box. Okay, So notice that have a gray box that is really only looking at a few of different. A few of the different structures were ignoring the methane. We're ignoring the co two. Why is that? Because in or go one, we're not really making a lot of these gasses. Okay, What we're really trying to do is we're trying to figure out how we can go from an alcohol toe alga. Hi. How we can go from Alba hide back to an alcohol stuff like that. We're trying to make sure that we know these transformations. Okay, So as we talk more about re agents in future topics, okay, or in later topics, we will focus on regents that make these transformations possible. Not the ones all the way to the extremes. Okay, so we're not gonna be in or go one. We're not going to turning methane into CO two. That doesn't happen in order one. Okay, cool. So let's just do some really quick practice. As I said, this is way easier than Redox reactions. You could just say, okay, are the following things are the following transformations and oxidation or reduction. So I'm gonna go ahead and give you guys some time. Go ahead and end the video, and then you guys will be able to select which one is the correct one. So go ahead and choose if this is gonna be an oxidation reaction or reduction reaction
2
example
Distinguishing between Oxidation and Reduction
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All right, guys, this first one was super easy. This is oxidation, okay? And the reason it's oxidation is because I'm adding to alcohols or to oxygen's to that double bond. Okay, Um, just, you know, in case you have learned this reaction already, maybe you haven't. But the name of this reaction was one to sin Di Hydraulics. Elation. Okay. And all that means is that you're adding to alcohol's on a double bond. You're adding them in the same direction. Okay. And there they are, visible to each other. Okay, instead of using the one two, you could also say that this is visceral sin. Die. Hydraulics. Elation. Alright. So that's the first answer. Go ahead and solve the second problem.
3
example
Distinguishing between Oxidation and Reduction
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Alright, guys. So this one was a little bit more challenging, but it's still pretty easy. This is a reduction. Okay? The reason this is a reduction is because if you'll notice the's carbons here had zero bonds to hydrogen. Okay, After the reaction takes place, have one bond to hydrogen here. One bond to hydrogen here. I've effectively added to hydrogen or what? We would consider one equivalent of hydrogen. Whenever I say in equivalent, that means you're adding two of them. All right. You may know this reaction or you may not. That's fine. But I just wanna let you guys know that you could have told if you did notice reaction, you could tell that it's a reduction just by the name. Okay, because the actual name of this reaction that that is taught in Orgel one is dissolving. Oops. Dissolving metal reduction. Okay. And in dissolving metal reduction, what we wind up getting is you are getting trans double bonds. That's just something that either you know what or you don't. But a triple bond turns into a dull bond that has a trans stereo chemistry. What's funny? What's cool about it is that if you remember the name. The name says it right there. It's a reduction reaction. We know that we're adding hydrogen. All right, so let's go ahead and move on to the last question. Go ahead and figure it out.
4
example
Distinguishing between Oxidation and Reduction
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54s
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Alright, guys. So this was obviously also a reduction. Okay. Why? Well, did we change the amount of oxygen's on this molecule? No, but we did change the number of hydrogen. Okay. Noticed that at the beginning. This had zero hydrogen. This had zero hydrogen. Okay, After my reaction takes place, I have one hydrogen here on. I have one hydrogen here. So once again, I have added to equip. I'm sorry. I've added to hydrogen or one equivalent of hydrogen. Okay, so just you guys know this is actually one of the types of transformations that we learned about with oxidation reduction. Okay, so I'm not gonna go into exactly what reaction this is right now. But you guys should just know that you can use a certain re agent to perform a reducing agent to perform this transformation. All right, so let's go ahead and move onto the next topic.