For this question, we have four chemical reactions for which we need to identify what is oxidized, What is reduced, What is the oxidizing agent and what is the reducing agent? The first chemical reaction is potassium reacting with water producing potassium hydroxide and hydrogen gas. If we assign oxidation states, elements by themselves have an oxidation state of zero, oxygen is always minus two, hydrogen is always plus one unless they're by themselves. So we go over to potassium, its oxidation state as its charge plus one. Again, oxygen is minus two, and hydrogen is plus one, But hydrogen here by itself is zero. So we see that water is being reduced. It has an element hydrogen that is going from a plus one oxidation state to zero. That reduction results in water being reduced, reduction and oxidation state means reduction and it then serves as the oxidizing agent. potassium, however, is going from a zero oxidation state. It is increasing an increase in oxidation state means oxidation. So potassium is oxidized and it serves as the reducing agent. It's always the opposite. Whatever is oxidized is the reducing agent and whatever is reduced as the oxidizing agent. The next one we have methane CH four reacting with oxygen producing carbon dioxide and water. When we assign the oxidation states, hydrogen is plus one, there are four of them, so that's plus four. So carbon needs to be minus four. Oxygen by itself has an oxidation state of zero, but in carbon dioxide it's minus two, there are two of them, causing carbon to have a plus four oxidation state And then oxygen and water has an oxidation state of -2 and hydrogen plus one. So we see in this case that methane has the element carbon that shows an increase in oxidation state. So methane is being oxidized and serving as the reducing agent, oxygen is going from a zero oxidation state to a minus two oxidation state in two separate compounds. So because oxygen has a decrease in oxidation state, oxygen then is reduced and it serves as the oxidizing agent. The next one is permanganate, reacting with iron two plus producing hydrogen ions are with hydrogen ion producing Mn two plus iron three plus and water. So if we assign oxidation states, oxygen is -2, there are four of them. So that's -8, So with -8, we need a plus seven, so that plus seven and minus eight gives us the charge of minus one. Oxidation states must always some up to the charge of the species Here, iron two plus its oxidation state is its charge, Hydrogen, its oxidation state is its charge. The MN two plus its oxidation state is its charge, and the F E three plus the oxidation state is its charge. And then in hydrogen, hydrogen is always plus one unless it's by itself and oxygen is typically -2 Unless it's by itself where it's zero. So here we see manganese and permanganate going from plus seven two plus two. That's a decrease in oxidation state. Therefore that's reduction. So we would say M n 04 minus is being reduced and it is serving as the oxidizing agent, the M N 04 minus as the oxidizing agent. And then we see Effie two plus going to F E three plus. That's an increase in oxidation state. An increase in oxidation state means oxidation. So F. E. Is being oxidized and it's serving as the reducing agent. And for the last one we have magnesium reacting with Copper two sulphate producing copper and magnesium sulfate. Magnesium by itself has an oxidation state of zero. Copper has an oxidation state of plus two, which is its charge, And then sulfate the whole charges -2. So the oxidation states need to send a -2 oxygen is minus two, but there are four of them, so that's minus eight. So we need a plus six to have everything some up to -2. Copper. All by itself has an oxidation state of zero. Magnesium has a charge of two plus. So it's oxidation state is two plus in magnesium sulfate and then the sulfate, oxygen and sulfur end up having the same oxidation states as they did over here. So we can focus on Copper. Copper is going from an oxidation state of plus 2-0. Therefore that's a reduction. So copper sulfate is being reduced and it's serving as the oxidizing agent and then magnesium goes from an oxidation state of 02 plus two. So it is being oxidized and serving as the reducing agent.