This question is going to take a look at an important chemical process or type of reaction called a redox reaction or oxidation. And reduction. And going to look at this with respect to a couple of different examples here. So the first example we're going to take a look at is going to deal here with a methane and reacting with uh water. So there should be a two there. So methane is going to react with water to form carbon monoxide and hydrogen gas. And one way that you can identify whether an oxidation reduction has taken place in reaction is look at what happens to the bonding between a species and oxygen. So if we look at what happens to methane, more specifically, the carbon and methane, it loses bonds to hydrogen and as a product gains a bond to oxygen or gains a triple bond, the oxygen, but in any case it's gaining bonds to oxygen throughout the course of the reaction. Whenever something gains bonds to oxygen, it has been oxidized or it's undergone oxidation. So methane has been oxidized here. So any time we talk about oxidation, it's a loss of electrons. So where do those lost electrons go? Um they have to go then to the water. And if we look at what happens to the hydrogen, specifically in the water molecule as it progresses throughout the reaction, it loses bonds to oxygen to become hydrogen gas. And any time also, we see a loss of bonds, oxygen just as gaining of bonds to oxygen means oxidation is taking place. If we lose bonds to oxygen, that means the species has undergone reduction and so water here is reduced or undergoes reduction, It's the species that's reduced. A couple of other terms. You should be familiar with oxidizing agent, reducing agent. So an oxidizing agent is always the thing that gets reduced throughout the course of a reaction. So who is reduced? Water? Therefore water is our oxidizing agent. In this example, a reducing agent gets oxidized. Who is oxidized? Methane was therefore methane is the reducing agent in this example. In the second example, we're looking at a silver nitrate and copper reaction here and here. It it kind of is a little more useful to look at assigning oxidation numbers to be able to see where the electrons are transferred in this reaction. So, copper, in its elemental form has an oxidation number of zero. Throughout the course of the reaction, it becomes copper nitrate nitrate ion has a minus one charge, and since there are two of them, they contribute -2 overall to the molecule. So copper then has a plus to charge in the copper nitrate molecule. So any time there's an increase in oxidation number. Throughout the course of the reaction, from reacting to product, copper goes from zero two Plus 2. That's an increase in oxidation number. That's a sign that oxidation has taken place. Therefore copper is oxidized in this reaction. And if we go to our terminology, a pure oxidizing or reducing agent. Ah but you can see here, okay, the thing that gets oxidized is are reducing agent. Therefore, since copper is oxidized, it is the reducing agent in this example. How about the silver? Alright, the silver goes from a plus one charge in the silver nitrate ion too. Remember copper was zero in its elemental form. So silver in its elemental form will be zero. Check it out guys. We see a reduction in the oxidation number. It's reduced from a plus one to a zero C. The terminology whenever something is has a lower oxidation number or state in the product form than it had in the reactant form. That's evidence that reduction has taken place. Therefore, silver and the silver nitrate has undergone reduction. Copper went underwent oxidation. So silver and the silver nitrate um underwent reduction and anything that's reduced throughout the course of a reaction is are oxidizing agent. So, silver nitrate in this example is our oxidizing agent. Now that you're catching on, I'm not going to spend as much time in the last two examples. But let's take a look at two more and follow the same ideas. This is zinc reacting with hydrochloric acid. So zinc starts out as a zero for its oxidation state, it becomes zinc chloride and it takes on a plus to oxidation state. What do we know? An increase in oxidation number means zinc has been oxidized the hydrochloric acid, The hydrogen goes from a plus one oxidation number two, Elemental zero anytime we see a reduction in oxidation number from plus 1 to 0 here, that's reduced. The zinc chloride then is reduced whose are oxidizing and reducing agent. Again, the thing that gets oxidized is are reducing agent. And the thing that gets reduced in this case, the hydrochloric acid, these are oxidizing agent. One final example, Um here we're going to look at the chrome eight and hydrogen ions, or protons. And so um if we identify here what's going on throughout the course of the reaction, it's a little bit of a trickier example. But let's look at what happens to the chromium whenever you see transition metals in a compound, especially when they're combined with oxygen, you want to think of um an oxidizing agent and you want to monitor what happens to that transition metal. So in this case, each of the oxygen is going to contribute -2 and have a -2 oxidation number four of them contribute -8 overall. And if we look at and you know, something wasn't right here, this should be a tu minus charge on the chrome eight. So, um in order to have an overall minus two charge, that means the chromium has to have a plus six. So plus six plus the minus eight gives that minus two charge that we expect on the chrome eight ion. Now, what happens to the chromium as it becomes a product, the same thing here, look at the oxygen minus two For each of the oxygen's, but there are seven of them. So all together they contribute -14. So in order to get a -2 overall charge in the Dike Romain Ion. And since I have two chromium, each of the chromium is has to have a plus six church Plus six times 2 is plus 12, 12 plus negative 14 gives the negative to charge on the dike Romanian. And look, there's been no change in oxidation number for the chromium. There's been no change in oxidation number for the other species, either the hydrogen or oxygen. So in this example, this is not a redox reaction because oxidation or reduction has not taken place on any of the reactant is involved.