10th Class Chemistry | Chemical Reactions and Equations | part 3

[00:00:02]Hello everyone, welcome back to Sai home school. Please like, share and subscribe my channel. Today we will discuss remaining topics from chemical reactions and equation. We already discussed two types of chemical reactions in the last session. Now we will discuss third type of chemical reaction that is displacement reaction. Displacement name itself indicates that what we can say displacement reaction what it means by so displacement reaction in the reaction in which one element get displaced with the another element it is nothing but replacement of a elements it will be takes place. If you observe one experiment here, here there is a copper sulfate solution.

[00:00:55]You dip the iron nail into the copper sulfate solution. You just observe the copper sulfate solution. Here it is blue in color. After dipping the iron nails, what will happen? We'll see through the reaction. When iron this this we should take this iron will be dipped in this copper solution.

[00:01:23]So you will get a copper sulfate solution you will get iron sulfate and copper will be separate. It means here what is happening in the place of this copper iron will attach means it will replaces the copper. Why it will happen? Because iron is more reactive than copper. If you observe that if you are present somewhere else what will happen? If person in front of you is more stronger than you, he will replaces you. That is how like that. So if iron is more reactive than copper. So that iron replaces copper as a product what you will get iron sulfate and copper will be separate. So if you observe the solution here before the copper sulfate solution when it is present it will be blue in color. After dipping the iron nail after that what is happening here? the solution will be light blue or sometimes it may be colorless. That is one example. So when you take a zinc, zinc you have to keep it in a copper sulfate solution. What will happen? Zinc will replaces copper. It will become zinc sulfate and it copper will be separated.

[00:02:54]Is it the reaction will be it is it possible this reaction? So that is why you have to know the metals which is more reactive and which is less reactive. If you observe this reaction zinc is more reactive than copper so that it replaces. Then if I take lead in a copper chloride solution what will happen?

[00:03:27]Lead this PB will replace as copper. It will become a lead chloride and [clears throat] copper will be separates. This is what now what is meant by displacement reaction is in a reaction in which one element get displaces with the another element that is called displacement reaction. Then finally it is double displacement reaction. It is the fourth type of chemical reaction. Double displacement name itself indicates what is happening here. Exchange it will be takes place.

[00:04:03]How the exchange of these elements we should not call here it is a element that we'll check with this example. You take a sodium sulfate solution and berium chloride solution.

[00:04:19]So what is happening here? Sodium will be replaces berium chloride.

[00:04:29]Then here it will be happen berium chloride will be at the place of sorry berium will be at the place of sodium here you will get a berium sulfate solution plus na solution here what will happen is so if you take a berium chloride solution so berium chloride it will be present in the test tube if you observe here there is The precipitation means precipitation means this is insoluble substance.

[00:05:05]So when if you take it into the that is which is insoluble in the water it will be as it is chloride it will be present in this. So this reactions see any reaction that produces precipitate means which is not soluble in water that is called precipitation reactions. This precipitation means itself indicates insoluble insoluble solid formed during the precipitation reaction.

[00:05:41]So for a board exams they will ask what is precipitation reaction here that is what we can say now is in the double displacement reaction we are taking a salts there is for the salts we have plus Ba plus Na plus SO4 minus BA plus CL minus here it is having positive and negative terms for the salt. So that here in the displacement reaction instead of calling elements we will tell exchange of ions between the reactants are called double displacement reaction. And before what we are telling combination reaction and decomposition reaction one element displays one product get breakdown into one reactant get breakdown into many products or maybe one reactant.

[00:06:46]Two or more reactant combine to form a single product. In this displacement reaction, more reactive element displaces less reactive element. Like that we are telling now it is in the double displacement reaction.

[00:07:06]What is we are telling? Exchange of ions means here salts we are taking that salts having ions positive and negative terms. So that these we will call the displacement reactions. Then finally one simple topic in this chemical reactions and equations is oxidation and reduction. As you know that what is oxidation? Oxidation is nothing but addition of oxygen. So what we'll tell in the reactions addition of oxygen takes place not only addition of oxygen and also it will be removal of hydrogen.

[00:07:48]So if you observe here copper will be heat in the presence of oxygen it will become a CO. What is happening here?

[00:07:58]Here only copper we have when we add or maybe if we eat in presence of oxygen what is happening in the product?

[00:08:07]Addition of oxygen to this copper then this reactions are called oxidation reactions.

[00:08:17]If for this copper oxide if you pass the hydrogen gas what will become? What it will become?

[00:08:27]The black coating on the surface turns brown means it will get again copper will be get we will get it back. It will be reverse reaction. So after getting a copper oxide if you add hydrogen to that you will get again reverse reaction it takes place means copper will be obtained back. These substances gains oxygen during the reaction that is get oxidized. These substances are called oxidation reaction.

[00:09:04]Sometimes what will happen some reactions during the reactions loss of oxygen or addition of hydrogen if it will be takes place then those reactions are called reduction reaction reduction reactions means addition of hydrogen here addition of hydrogen and removal of oxygen that is called reduction ction reaction. So these oxidation and reduction both it will be takes place in a single reaction that is called redux reaction. If you observe the below example. So if you see under this here there is a removal of oxygen or loss of oxygen from the copper oxide you are getting only a copper. If you see above this one there is a addition of oxygen. Here we have only hydrogen and the reactant side. When it comes to the product side there will be a H2O here. What is happening? Gain of oxygen that is redux reaction reduction and oxidation both it will be takes place in a same reaction means hydrogen is gaining oxygen copper oxide be removal of oxygen. So if you take some more example zno plus c. See here what is happening from Z and O loss of oxygen here if you come to the product there is a loss of oxygen if you see the carbon it will become a carbon monoxide gain of oxygen addition of oxygen takes place means oxidation removal of oxygen is called reduction that is in The reaction in which involve both oxidation and reduction then the reaction will be called redux reaction.

[00:11:26]Then in exams they will give one this type of one example then they ask you to show where is oxidation takes place and where the reduction takes place. you should should be very important. Then the final topic in this chapter is corrosion and rancidity. Did you observe the effects of oxidation in our life?

[00:11:56]Yes, of course. How it will be mean? You bring some iron article without coating or without painting, without giving any coating. For that you keep it for the expose it to the atmosphere in your home. What will happen after 4 5 days you have to observe is it the color of the iron will be same or maybe any changes it will be occurred.

[00:12:20]You have to observe. So if you observe the color maybe it may be changes and if you observe above the iron you may see some like salt salts that what is that is called rust that is in the presence of the process rusting of iron or maybe any metals that will get change its color or It will get rest when the metals attached by the surround substances around it like moisture or maybe acids or maybe it will be reacts with the oxygen they will get corroded. Corro means they will get rust that is called corrosion. Overall definition what we can say for the corrosion is some metals reacts with the substances around it like oxygen or maybe moisture or maybe acids and it will get corrod that process what is happening the process for this no to get rest after getting reaction takes place around with the surrounding substances and it will get cor maybe it will get change its color that we will call it as a corrosion. So the black coating on the silver and green coating on the copper for the other examples of corrosion. Iron will get turns brown color rusty then silver will turns into black color if you observe the silver silver articles without closing if you keep expose it to the atmosphere in your home. So you keep silver articles even outside for a few days what it will become? It will change its color. It will become a black color.

[00:14:19]If you take a copper articles then you should keep it for outside it will turns into a green that is called corrosion.

[00:14:30]Corrosion because of this corrosion there is so many problems we will face.

[00:14:34]So if you observe wherever we'll see that there is a more iron will be used to made some materials that is damage of car bodies because of this corrosion bridges they will use more iron to construct the bridges when the iron nails get starts rusting it also starts breakdown then iron railings then ships and all objects of metal Whatever the metals made sorry objects made up of these metals so that it will be get corro we will get some serious problems from this corrosion.

[00:15:20]So if you observe this corrosion where more of the problems will be occurred in this corrosion is where they will use the iron. So replace will be damaged iron. So it will be where the iron will get rust and where the metals they will use will start exposed when it exposed into the atmosphere they will start getting spoils. Then so there is a more problems will be occur from this corrosion. Then it is a rancidity. Here what we observed is for the moodles. So rancidity will be takes place for the food materials that is if you keep some food outside or fat and oil containing foods for long time what will happen? For example, if you bring the chips from the bakery you have to open and keep it for 2 or 3 days. If you observe the taste of the chips will be same as first you bought from the bakery. No because of it will get the fats and oils are oxidized and it will become rancid. When it will become rancid it will changes its smell and also taste that is called rancidity.

[00:16:47]So what is meant by rancidity? When fats and oils react with the oxygen or it will go under oxy undergo oxygenation their smell and taste changes. This process is called rancidity. The process of spoiling the food by changing its taste and smell. This process what is going on all these after reacting with atmospheric oxygen that is called rancidity.

[00:17:17]So if what we what we should do to avoid this rancidity one important question how do you how do you prevent rancidity?

[00:17:27]So we should prevent the rancidity by adding some antioxidants. So here name itself indicates here it is going oxidation is taking place for the food and oil fats and oils. So that we have to use antioxidants to avoid the rancidity for the food items. So if you observe the chips cover it will be more gas will be filled in it. Here most preventing antioxidant more we are using that it is nitrogen gas. If you observe the chips cover there will be they flush the nitrogen gas into the chips cover then they pack. If you open that if that nitrogen gas will be liberated when that food will be reacts with the oxygen then it changes its smell and taste. That is the thing how the food will get spoiled that is called rancidity. So thanks for watching. Please subscribe my channel.

[00:18:37]So for next session we will discuss question and answers for this chemical reactions and equations.