 In this video, we are going to talk about bleaching powder and you might be using this at home. We will see how this is chemically made and what are its uses. So, let's begin. So, bleaching powder, this is chemically known as calcium oxychloride. And this is formed when chlorine is passed over, chlorine gas is passed over, dry slagged line. Okay? So, let's write down the chemical reaction. So, chlorine gas is Cl2. And when this is passed over, dry slagged line. Do you remember what is the chemical formula of slagged line? Well, let me help you recall this. So, in chemistry, whenever we say lime, we do not mean lemon. But we mean calcium oxide, also known as quick lime. And this is called quick because it quickly combines with water. With water, there will be combination reaction. And finally, we will get calcium hydroxide or wet lime. And this is called as slagged lime. So, basically, we are drying this out to remove excess water. So, the chemical formula is going to be same, calcium hydroxide. Let me write the same color. CaO whole twice. And these both are going to react. And finally, we will get calcium oxychloride. CaOCl2. And with this, we also get water plus H2O. So, this is how you form bleaching powder. You pass chlorine gas through dry slagged lime and you get calcium oxychloride or bleaching powder. By the way, the actual formula of bleaching powder is slightly more complex. To understand that, we will have to study many more concepts. So, we will do that in future videos. But for now, just understand that bleaching powder is calcium oxychloride and its formula is CaOCl2. With this, I would like to tell you one more thing. This is bleaching powder is one of the compounds that is formed with the help of sodium chloride, NaCl, the common salt that we use in our kitchens. Yes! See, to make this, we required chlorine gas, right? And you would remember that chlorine is one of the products, the byproducts that gets formed when we do electrolysis of NaCl, aqua solution of NaCl. When we pass electricity through a solution of water and NaCl, chlorine gas was also getting evolved. And this chlorine gas could be used to make bleaching powder. That's what makes NaCl so great and important because it can be used to make many other chemical products. So, now with this, let's go ahead and see what are the uses of bleaching powder. So, the first is, it is used as oxidizing agent in chemical industries. See, bleaching powder is a very good oxidizing agent. Now, what do I mean by that? So, you would recall that oxidation is oxygen's addition. Meaning, if oxygen is getting added to any element or a compound, that means they are going under oxidation. For example, carbon plus oxygen. This gives us carbon dioxide. So, here oxygen was getting added to carbon. That means carbon is going under oxidation. It is getting oxidized. And we are getting a new compound altogether. So, bleaching powder is a very good oxidizing agent. This means that this can easily oxidize other compounds and elements. It can easily add oxygen to other compounds and elements. And so, whenever this is required, whenever we require to add oxygen to something in chemical industries, we use bleaching powder as oxidizing agent. Now, another use is to decolor or bleach certain materials. For example, if you want to decolor cotton or linen in textile industries. See, my favorite t-shirt is black in color. But it is made up of cotton, cotton material. And cotton is not naturally black in color. So, how did this color happen to come over here? So, I guess the makers of the t-shirt, they would have put the cotton t-shirt into a black colored dye. And the molecules of the dye, they would have got stuck on this t-shirt. And that's how my t-shirt appears black in color. So, now when I put this in bleaching powder, the molecules of the bleaching powder, they will oxidize the black colored molecules of the dye. And then chemical reaction happens and a new compound gets formed. And this has lost its black color. And that's how my t-shirt, it loses its black color. It has become faded. So, that's how you can use bleaching powder in textile industries to bleach cotton and linen. You can also use it to bleach your jeans and give it nice shaded look. But be very careful while trying this at home. Okay, we also use bleaching powder to decolorize wood pulp in the paper industry. See, the paper that we use is very white in color. It's made from wood pulp, which is not very white in color, right? So, to decolorize this wood pulp, we use bleaching powder. And similarly, we also use it to bleach or remove stain from clothes. See, whenever there is some stain or some color mark on your clothes, that's very strong color, right? And to remove the color or to decolorize it, we can use bleaching powder for the same thing. One more use case of bleaching powder is for disinfecting water. See, water can have many microorganisms in it, which could be very harmful for the human body. So, when we mix bleaching powder in water, it gives off chlorine. And chlorine is toxic for the microorganisms. It even kills them. So, that's why drinking water is first treated with bleaching powder before supplying it to our houses. And for the same reason, we also treat our swimming pool with bleaching powder. And that's why it smells of chlorine afterwards. Now, let's summarize the video. In this video, we talked a lot about bleaching powder. We saw what is its chemical formula. We saw how to prepare it. And we also saw that it has two properties, one that it can oxidize and the other that it is toxic. And based on these properties, it has got some uses. Based on oxidizing capacity, it is being used in chemical industries, paper industries and in textile industries. I hope you remember how. And based on its toxic property, it is used to treat water. Now, I hope you recall all of these things and if you don't, you can go back and watch the video again.