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Video transcript

- In this video, we are going to talk about baking soda. You might have seen this white power in your kitchen. We use this to make puffy bhaturas, or samosas, or to bake soft cakes. So first of all in this video, we will se how baking soda is made. Then we will look at its uses. Let's begin. Baking soda is chemically known as sodium hydrogen carbonate. It is chemical formula is NaHCO3. Now let's try to guess what chemical compounds would have reacted to give us this compound, sodium hydrogen carbonate. Can you pause the video and guess this by yourself first? If you have tried it, let's see. If I had to take a guess, I see a sodium in the formula, right? I will say that sodium chloride is reacting and sodium is coming from there. Then I see a carbon, so then I would guess that carbon dioxide is also involved in the reaction. That's where we get this carbon. Since there is hydrogen, I'll guess hydrogen is coming from water. My guess is going to be sodium chloride, water, and carbon dioxide. These three are reacting to give us NaHCO3. Let me just write it down. There is one more ingredient, one more compound that goes into this mixture. That is ammonia, NH3. Sodium chloride water, carbon dioxide, and ammonia all react and NaHCO3 is formed. With this we get one more product, NH4Cl, ammonium chloride. So to make baking soda, I need four ingredients: sodium chloride, water, carbon dioxide, and ammonia. Don't forget this one. I usually forget this one. Don't do this mistake. We need four reactants and then I'll get baking soda or sodium hydrogen carbonate, and along with this one more product is getting formed, ammonium chloride. Now let's look at the common uses of baking soda. We use baking soda to make puffed bhaturas or samosas. Puffed basically means inflated with gas. How this is done is we mix some baking soda in the flour. Flour basically means atta. When this is deep-fried, the baking soda gets heated up and it decomposes to give carbon dioxide gas. The reaction looks something like this. Baking soda on heating. It will decompose to give sodium carbonate, Na2CO3, water, and carbon dioxide gas is released. This gas gets trapped inside. That's why our bhatura looks very puffed. See over here, samosa also looks very puffed, right? The same thing can also be used to make soft cakes. You would have seen that cakes have holes in it and they are very soft and spongy, right? Something very similar is happening to make them soft and spongy. Over here also, when they are being baked, carbon dioxide gas gets produced and it gets trapped inside. It's trying to escape. Because of which the cake becomes very puffy. It becomes soft. But there's a problem. If I had mixed baking soda into the dough of the cake and when I had heated it, this would have decomposed to give me carbon dioxide definitely, yes that is helpful, but also with that I would have got Na2CO3 and this is basic in nature. Now you will think, "Why is that a problem?" You might recall that bases taste bitter whereas cakes are supposed to taste sweet, right? This is going to spoil the taste of our cake and that's what we don't want. So that's why we do not use baking soda to bake cakes. Instead we use baking power, which is a mixture of baking soda and a mild edible acid, tartaric acid. So we mix baking soda with tartaric acid and we get baking powder. If you're wondering what is the chemical formula for tartaric acid, don't worry about that. Just know that tartaric acid has H plus, it can give H plus ion because it's an acid and it has some negative ion. Some random negative ion. I'm denoting that with X minus, so it's chemical formula will be "HX," just to keep things simple over here. Now you might be thinking, "what is the chemical reaction that's happens here?" Let's do that. Over here, we will get a double displacement reaction and the ions are goin to exchange position. Now sodium plus ion will get attracted to X minus ion, whatever the X was, and we will get NaX. This will be a salt. Our H plus will now get attracted to HCO3 minus. We will get H2CO3. Plus H2Co3. We have seen that this is not very stable. This will quickly decompose. This will quickly breakdown into water and carbon dioxide. Let me just remove it. H2O and carbon dioxide. Carbon dioxide gas will be involved here. In this case also, we are getting carbon dioxide gas, which will make the cake very soft and fluffy. In this case we are getting NaX, which is a salt and this will not spoil the taste of our cake. That's why this is a good combination to use to bake cakes or cookies. Since baking soda uses carbon dioxide, it has got a lot of use in cooking. For the same reason, it is also used in fire extinguishers. Carbon dioxide can extinguish fires, and that's why we use baking soda in soda-acid fire extinguishers. Also, baking soda is basic in nature so this can be used as an antacid. If you have an acidity, or excess buildup in your stomach, then you can take a little bit of baking soda and this can neutralize the acid buildup in your stomach and give you relief. Since baking soda is basic in nature, it can be used as an antacid. If you're wondering, "How is baking soda basic in nature?" Baking soda is a salt, NaHCO3 and we can try to find out its nature. Salts can also be acidic or basic, right? Let's write out its acid and base and then try to find out its nature. The base over here would be NaOH. NaOH. The acid would be H2CO3. We know that this base is a strong base and this acid is a weak acid. Whenever a strong base reacts with a weak acid, we get a basic salt. So this is going to be a basic salt. If you do not understand what I did over here, then don't worry. I have talked about this. We have studied this in detail in a separate video, so you can watch that and come back over here. This tells us that NaHCO3, or baking soda, is basic in nature. That's why we can use it as an antacid. Let's summarize the video. In this video, we spoke a lot about baking soda. We looked at its chemical formula and also how it gets prepared. I hope that you remember how many reactants were involved to make this and what were those reactants. We also saw that baking soda has two properties. One, that it gives out a lot of carbon dioxide gas and based on this property, we saw two use cases of baking soda. The other property was that it is basic in nature and based on this, we saw the third use case of baking soda. I hope you remember all of these points. If you don't, then don't worry. You can go back and watch the video again.