 In this video, let's try to solve some problems on identifying different types of chemical reactions. So this is my first problem. I have been given four chemical reactions and I have to identify them as combination reaction, decomposition, displacement and double displacement reaction. So before I solve this for you, why don't you pause the video and try it yourself? Now if you have tried it, let's see. Let me first of all hide the cushion so that I have some space to write over here, okay? Now the first reaction. Here I have iron sulfate on the reactant side and on the product side, I'm getting iron oxide, sulfur dioxide and sulfur trioxide. So I can notice that I have one reactant and I have multiple products. So over here I see that one reactant is breaking down or decomposing into multiple products and that is an example of decomposition reaction. Decomposition reaction. In decomposition, one reactant breaks down into multiple products. Now let's look at the another one. Over here I see that I have hydrogen and oxygen on the reactant side and on the product side, I'm getting water, H2O. So I notice over here that I have multiple reactants but only one single product. So we can say that here the reactants are combining to give me one single product and this is an example of combination reaction. Let's write down combination reaction. In combination, multiple reactants combine to give us one single product. Let's look at the third question. So here I have iron and copper sulfate on the reactant side and on the product side I'm getting iron sulfate and copper. So I can notice over here that iron was alone previously and copper was in its sulfate form but later on iron is taking the place of copper and is forming the sulfate and copper is left alone. So I can say that iron is displacing copper from its sulfate and forming iron sulfate and these kind of reactions are called displacement reactions. Displacement reactions where one more reactive element displaces another one from its compound. Now let's look at the last part. Berium chloride plus hydrogen sulfate gives me Berium sulfate plus hydrogen chloride. So I can notice over here that, you know, Berium was initially combined with chlorine and hydrogen was initially with sulfate but later on what is happening that Berium is switching places is getting combined with sulfate and similarly hydrogen is switching places. It is getting combined with chlorine. Berium forms Berium sulfate and hydrogen forms hydrogen chloride. That means over here in the reactants the ions are exchanging position and whenever that happens we call it a double displacement reaction, a double displacement reaction. In this the ions of the reactants they exchange places. Okay, now with this let's try to solve another problem. So here I have some reactions and I have to identify them as exothermic or endothermic reactions. Now before I solve this, why don't you pause the video and give it a try. Now if you have tried it, let's see. See in the first reaction, iron sulfate is decomposing into multiple products. Now if you do not remember the actual experiment it will be hard for you to tell whether this is endothermic or exothermic reaction but we have a trick. See, we know that this is a decomposition reaction and we have also seen that in general decomposition reactions require more energy to even start to break down, right? And we know that reactions that require more energy are called endothermic reactions. So in that case I'm going to guess that this reaction is going to be endothermic nature. And that will be a correct guess because you know when you're doing the actual experiment you will have to heat up iron sulfate and then only it will decompose and you wouldn't get any heat or light in this experiment. That's why this is endothermic reaction. Now if you're wondering Ram, how do I remember that you know decomposition reactions are endothermic generally? So for this I use the magnet analogy. See, when two magnets are stuck and I have to pull them apart I need to provide in energy, right? Similarly when atoms are stuck in a molecule and I want to you know separate them I need to provide energy and same thing is happening over here. There is a big molecule and I want to pull apart some atoms then only I'll get multiple products, right? So for this I have to supply in more energy and that's why endothermic. And again, this is not the reality. In reality many more things are also happening but this is a good memory aid to remember that decomposition reactions in general are endothermic in nature. Okay, now let's move on to the next one. So here I have hydrogen plus oxygen. This gives me water. So this is a combination reaction and we also see that it's written plus heat on the product side. Now this symbolizes that heat is being released along with the products. Now since it's already given to us that heat is being released then we can guess that or we can tell that this is an exothermic reaction. In exothermic reactions heat is released. This is exothermic reaction. And if plus heat wasn't written then I could have also taken a guess. See, this is a combination reaction and generally in combination reactions heat is released. Now for this also I have a magnet analogy to remember this. See, here when two magnets that are attracting they come close together then they release sound energy. Similarly when two atoms when they're attracting each other they come close then they release energy. Similarly over here you can see that hydrogen and oxygen are kind of combining, right? And that's why they will release energy which means that they will be exothermic reaction. Now again in reality many things are happening over here. So this is just a memory aid to help you remember that combination reactions in general will be exothermic in nature. Now let's solve the last part, respiration. Now see, this is the process by which our cells break down glucose and in the process we gain a lot of energy which we can use to run and play and do all sort of activities. And that's why respiration is an important process for our bodies. Now see, since this process is giving out more energy we call this process as exothermic. This is going to be exothermic process. Now with this done let's do one last problem. So this is the last reaction. In this one we have to identify which element is going under oxidation and which is going under reduction reaction. So why don't you pause the video first and try this by yourself. Now if you have tried it let's see. First of all let's try to recall what do we mean by oxidation and reduction. So see as the name suggests oxidation means oxygen's addition. Meaning if any reaction oxygen is getting added to an element or if in terms of hydrogen we will say opposite. Hydrogen is getting removed from an element then that element is going under oxidation. If we have to talk about reduction so that would be opposite. In reduction if oxygen is removed from an element or hydrogen is getting added to an element then we will say that that element is going under reduction reaction. Now with this let's try to see what is going under oxidation and reduction here. So here I see that hydrogen was alone at first but after the reaction hydrogen is combined with oxygen. That means that oxygen got added to hydrogen. That means hydrogen element is going under oxidation. Oxygen was added to it. Whereas if you see oxygen oxygen was alone to begin with but after the reaction it's added with hydrogen. That means hydrogen got added to oxygen. So oxygen must have gone under reduction reaction. Reduction reaction because hydrogen is getting added. And in this reaction since both oxidation and reduction are happening this is an example of redox reaction. Now with this we have seen all types of reactions and we have also applied them in various examples.