Classify each reaction as an oxidation, a reduction, or neithe...

Question

Classify each reaction as an oxidation, a reduction, or neither.

(j)

(k)

(l) Chemical reaction showing the conversion of a cyclohexene to cyclohexanol using BH3 and H2O2.

Accepted Answer

All right. Hello everyone. So this question is asking us to determine if each is an oxidation or reduction reaction or if it is neither of the two. And here we have three reactions labeled 123. However, of the three of them, only part one is two steps. But before we talk about each synthesis individually, let's go ahead and recall what it means when we describe a reaction as oxidation or reduction, because there is a way to determine whether or not a reaction is oxidation reduction or neither without necessarily calculating the oxidation state. First, recall that oxidation can mean a few different things when analyzing the starting material and the product, we can note an increase in either carbon oxygen, carbon nitrogen or carbon halogen bonds or a halogen is abbreviated here as X. So an increase in any of these types of bonds would count a certain reaction as oxidation. However, in addition to this, we can also note whether or not there is a decrease in carbon hydrogen bonds because in a decrease in carbon hydrogen bonds could also count a reaction as oxidation too. So with this in mind, we can go ahead and count a reduction as the opposite. A reaction can be counted as a reduction if we see a decrease in carbon oxygen, carbon nitrogen or carbon halogen bonds. Therefore, an increase in carbon hydrogen bonds could also count a reaction as a reduction. So with all this in mind, which reactions then count as neither oxidation nor reduction. Well, there are a few different examples because for example, the addition or removal, that's the loss of either a proton water HX where X is a halogen, as well as a few different types of reactions do not necessarily count as neither an oxidation nor a reduction. So with these definitions in mind, I'm going to go ahead and scroll up here. So we can consider the first reaction. Now, part one is actually a two step synthesis. So let's consider each individual step starting off here. Our starting material for part one is an keen and the keen is reacting with a perox acid to produce an oxide ring. Now, notably, the carbon, carbon pi bond has broken and it's been replaced with new carbon oxygen bonds. So in the first step of part one here, we're seeing an increase in the number of carbon oxygen bonds when comparing the starting material to the product or at least the intermediate in this overall synthesis. Because of this, the first step is an oxidation. So now when considering the second step are oxide ring in the presence of dilute acid is going to open to create a trans dial as well as in an numer. Now, in this particular case, we have the addition of water across the epoxy ring to open set oxide ring. And notably in the oxide intermediate, we have two carbon oxygen bonds in the oxide itself. And the number of carbon to oxygen bonds has actually stayed the same in the structure of the final product. So because of this, the second step of the first reaction for part one here is neither oxidation nor reduction. And so with that in mind, we can proceed to part two. Now, for part two, our starting material is once again an all keen, we have cyclopse here reacting with BR two in the presence of water to produce a halo hydrant. Now, notably, the keen has been converted into a halo hydran in which we now have a new carbon halogen bond, specifically a carbon B roaming bond and we have a new carbon to oxygen bond. So in this case, there is an increase in carbon halogen and carbon oxygen bonds, meaning that the second reaction is an oxidation. Keep in mind that the halo hydrants in numer is also produced. So last but not least in part three. Here we have Cyclin as our starting material undergoing hydro beration oxidation to produce cyclops. Now, it's worth mentioning that in the structure of the final product, we are seeing an increase in carbon oxygen bonds But what I do want to recall is that hydro beration oxidation is the addition of water across both carbons of the starting. This means that the second carbon of the ane itself also gained a carbon hydrogen bond. So what that means to say is that the third reaction here has no net oxidation or reduction because while the number of carbon oxygen bonds has increased, so has the number of carbon hydrogen bonds. So the third reaction is neither and there you have it. So here I briefly paused the recording. So I could write out the final answer on the bottom of the screen. So the final answer is as follows. For part one, the first reaction was oxidation and the second reaction was neither oxidation nor reduction. Part two was oxidation and part three was neither an oxidation nor reduction. So with that being said, thank you so very much for watching. And I hope you found this helpful.

Classify each reaction as an oxidation, a reduction, or neither.
(j)
(k)
(l)

Key Concepts

Oxidation and Reduction

Oxidation States

Redox Reactions

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