FUNCTIONAL GROUPS TEST OF ORGANIC COMPOUNDS

[00:00:01]All right.

[00:00:03]Good morning, students.

[00:00:06]In this video, I'm going to be teaching you functional group text of the following homologous series.

[00:00:16]The first is the alkane, the alkene, the alkynes, the alkyl halides, which are called the halogenoalkanes, the alkanols, the phenols, alkanoic acids, aldehydes, ketones, esters, amides, amines, carbohydrates, amino acids, sugars, etc. So, we are going to discuss all these tests.

[00:00:56]We are talking about how to determine the functional group in each of these So, I am going to start from alkane. We are going to start from alkane.

[00:01:06]I'm going to start from alkane.

[00:01:09]Okay?

[00:01:12]So, for alkane, alkene can be identified using two tests. We can use two tests to identify alkane.

[00:01:24]The first one is called the KMnO4 test, which is popularly known as Baeyer test. This is also called the Baeyer test.

[00:01:39]The second one is called the bromine water test.

[00:01:44]Is the bromine water test. So, these are the two tests that we are going to use to confirm for alkane.

[00:01:53]And you know that these two tests, we can use it for saturated and unsaturated text to confirm alkane also.

[00:02:03]Now, if I pick the first one, which is called a Bayer test, the first question is this, does alkane react with KMnO4?

[00:02:15]If I have this as an alkane plus KMnO4, what am I going to observe?

[00:02:24]Now, we know that the functional group that is present in alkane is carbon-carbon single bond.

[00:02:32]This is a functional group that is present in alkane.

[00:02:37]And KMnO4 >> [clears throat] >> KMnO4 can only react or readily react with this carbon-carbon double bond or in the presence of carbon-carbon triple bond. This is because this contains a pi electron and this equally contain Sorry, contains a pi electron. This contains pi electron.

[00:03:05]This contains pi electron also.

[00:03:08]So, if alkane is treated with KMnO4, what happens is that there will be no reaction. So, the purple color the purple color the purple color of the KMnO4 will remain.

[00:03:25]But, when you treat KMnO4 in the presence of any compound that contains this, double bond, we are going to have a reaction where the purple color will disappear.

[00:03:38]Also, in this format, it is also going to do what? Disappear.

[00:03:43]So, let's begin with a practical example.

[00:03:48]So, when you look at this, if you are asked to determine this test, see what you write. You say add KMnO4 to suspected alkane.

[00:03:58]When you add this to a suspected alkane, remember that this is your test.

[00:04:04]This is your what?

[00:04:05]Your observation. And this is your what?

[00:04:08]Your inference.

[00:04:10]Now, when I add this to a suspected alkane, am I going to notice any reaction?

[00:04:16]The answer is no.

[00:04:17]For I will write that purple color I will write in my observation purple color of KMnO4 remains.

[00:04:33]This is what I'm going to write.

[00:04:35]So, if you like, you can write no decolorization.

[00:04:40]You can also write or you can write no what?

[00:04:44]Decolorization.

[00:04:48]You can write no decolorization.

[00:04:51]What is the meaning of this decolorization?

[00:04:54]In chemistry, the word D simply means to remove.

[00:04:58]So, in chemistry, in chemistry, the word D simply means to remove.

[00:05:04]This is color. So, when they say decolorization, it means removal of color. Are we going to observe a removal of color or is it that the color remains?

[00:05:16]So, if you say no decolorization, it means that there is no color removal.

[00:05:22]So, which means that reaction has not occurred.

[00:05:26]So, what I'm going to write is purple color of KMnO4 remains or you can say no decolorization.

[00:05:35]Now, what is my inference? I will say alkane alkane is what?

[00:05:43]Present.

[00:05:45]Alkane is present is going to be my inference. Remember the text says we should describe how we would, you know, determine that an alkane is present in an organic sample. So we said the first test is Bayer test. Add KMnO4 to suspected alkane.

[00:06:05]Purple color of KMnO4 remains. It means that the alkane is what? Present.

[00:06:13]So, the second test, the second test is bromine water test. Bromine water test.

[00:06:25]Is bromine water test. Now, what happens is that when alkane is treated with bromine water, if alkane is treated with bromine water, what are we going to observe?

[00:06:41]We observe that there will be nothing like a reaction.

[00:06:45]So to say that the color of the bromine water will not change. So it will remain.

[00:06:52]Now, but I want you to know that when an alkane reacts with the same bromine water, bromine water, and then in the presence of a UV light or strong heat, we know that everybody know this reaction. This is called bromination.

[00:07:11]In the presence of what? A UV light or strong heat, we are going to a reaction.

[00:07:17]There will be a color change here.

[00:07:19]There's going to be a color change. The reason is because of the presence of this UV light.

[00:07:25]But if an alkane is treated with a bromine water ordinary condition, it means that there will be no reaction.

[00:07:33]The color of bromine water will remain.

[00:07:36]There will be nothing like decoloration.

[00:07:38]So we are not going to observe any decoloration of the bromine water.

[00:07:47]So, we say there will be nothing like a decolorization of the bromine water.

[00:07:54]So, what am I going to write?

[00:07:56]The text is add add bromine water.

[00:08:04]Add bromine water to the suspected what?

[00:08:12]To the suspected alkane and see what will happen.

[00:08:17]If I add bromine water to the suspected alkane, are we going to have any reaction? The answer is no.

[00:08:23]So, I can comfortably write that bromine water color remains.

[00:08:28]I can say bromine water color remains. That's what I will write. I can say the bromine water color remains, okay?

[00:08:49]I can say the bromine water color remains.

[00:08:52]Now, it means that alkane also alkane is present.

[00:09:01]Alkane is present.

[00:09:04]This is also the text on how we can confirm the presence of alkane using bromine water.

[00:09:13]So, this is what I have.

[00:09:16]We need to go to the next one, which is called alkane.

[00:09:21]All right, for alkane alkane contains carbon-carbon double bond and alkyne contains carbon-carbon triple bond. So, here mix will react with KMnO4 and X will also react with KMnO4.

[00:09:44]Two of them will react, so we are going to observe a decolorization.

[00:09:51]And we're also going to observe a decolorization here.

[00:09:55]Also, in the presence of bromine water in the presence of bromine water, this reaction will also occur.

[00:10:03]We are going to observe decolorization here, also decolorization here.

[00:10:11]So, when you look at this test, this is also this is also Baeyer's test.

[00:10:19]This is also Baeyer's test, okay?

[00:10:22]Which talks about KMnO4.

[00:10:25]Now, I said, "Add KMnO4 to the suspected alkene and see what will happen."

[00:10:33]What are we going to have? There will be reaction.

[00:10:36]So, which means that purple color purple color of K KMnO4 disappears.

[00:10:51]The purple color disappears.

[00:10:53]Or you can write decoloration.

[00:10:56]The purple color disappear.

[00:10:59]Or you can write what?

[00:11:01]Decolorization.

[00:11:03]Okay?

[00:11:04]So, if that is the case, what I'm going to write in my inference is what?

[00:11:08]Alkene.

[00:11:11]Alkene is present. That is what I have.

[00:11:15]So, I have that alkene is present.

[00:11:18]Why? Because purple color of KMnO4 disappears.

[00:11:25]This is a test to confirm the presence of alkene.

[00:11:32]So, the second test the bromine water test.

[00:11:36]Bromine water test, will bromine react with alkene? The answer is yes.

[00:11:40]Bromine react with alkene and alkynes.

[00:11:44]Now, what I'm going to have is also the same thing. I can say decolorization of bromine water.

[00:11:54]I can still write that.

[00:11:56]I can say the purple color disappears.

[00:12:01]So, which one is part So, I will have decolorization of bromine water.

[00:12:14]I can put observed.

[00:12:20]Decolorization of bromine water observed.

[00:12:23]And then, what am I having in my inference?

[00:12:26]Class, what I will write here will be that alkene alkene is present, also.

[00:12:36]This is because it contains carbon-carbon double bond. You know that the same test here will also happen to that of the triple bond.

[00:12:45]And this test is called a Bayer test.

[00:12:47]This is my test. This is my observation.

[00:12:51]And this is my what? My inference.

[00:12:55]So, this is exactly what I'm going to be having for this.

[00:13:01]So, class, the third one is for alkyne, functional group test for alkyne.

[00:13:06]The functional group test for alkyne the functional group test for alkyne So, we want to also use the Bayer test.

[00:13:15]Alkyne can also be determined using Bayer test and bromine water test. Remember I've explained that they react. So, add KMnO4 to suspected alkyne. What are you going to observe?

[00:13:29]We are going to have that a purple color.

[00:13:32]We have that a purple color.

[00:13:36]Purple color of KMnO4 disappears.

[00:13:48]Disappear simply means that there is reaction that is going on.

[00:13:53]So, one can now say that alkyne is what? Present.

[00:14:02]Alkyne is present.

[00:14:04]This is how you can love it.

[00:14:07]So, for alkyne for alkyne let's talk about Bayer test for alkyne.

[00:14:15]Bayer test for alkyne.

[00:14:18]Bayer test for alkyne.

[00:14:21]So, for alkyne alkyne it contains a carbon-carbon triple bond.

[00:14:27]Are they going to react with KMnO4? The answer is yes. Oxidation of alkynes can occur.

[00:14:35]So, add bromine water. Sorry.

[00:14:37]Add bromine Okay, sorry. This one is not uh Bayer test. We have discussed Bayer test. Sorry.

[00:14:45]We have discussed a Bayer test. This one is bromine water test.

[00:14:51]This one is bromine water test.

[00:14:55]We have discussed a Bayer test. Okay?

[00:14:58]This particular one is bromine water test. So, when you add bromine water to the suspected alkyne, we are going to observe reaction.

[00:15:07]Yes, we are going to observe what?

[00:15:09]Reaction. And which means that we are going to observe a decolorization of the bromine water. So, we say de- colorization.

[00:15:27]of bromine water.

[00:15:32]So, that we can now confirm that alkyne is what? Present.

[00:15:40]So, you must try to take note of all these things.

[00:15:44]You must try to take note of all these things one after the other.

[00:15:48]How it works.

[00:15:50]So, we know that alkane, which is a carbon-carbon double bond, they react with KMnO4, yes.

[00:16:01]Telling us that the purple color will disappear.

[00:16:04]Here, the purple color disappears.

[00:16:08]Then, also in triple bond, they equally react with this and the purple color does what? Disappears.

[00:16:16]And also in the presence of bromine water, in bromine water, what happens?

[00:16:22]Bromine, we have reaction also here.

[00:16:25]What happens? We equally have what?

[00:16:27]Reaction.

[00:16:29]So, there is a particular test that we are going to use to distinguish between alkyne and what? Alkene.

[00:16:38]So, there are these these reagents that I normally use to distinguish between them, which I can use one, which is called a Tollens' reagent.

[00:16:48]I can use the Tollens' reagent.

[00:16:52]I can use the Tollens' reagent, which is an ammoniacal solution of silver nitrate.

[00:17:02]This is ammoniacal. This is ammoniacal.

[00:17:06]Ammoniacal solution of silver nitrate.

[00:17:13]When we say ammoniacal solution, it is a solution that contains ammonia and silver nitrate.

[00:17:20]So, we can use that to do what?

[00:17:24]To differentiate between them.

[00:17:26]Now, this Tollens reagent is an oxidizing agent.

[00:17:31]So, because it is an oxidizing agent, we can simply explain that this particular one, terminal alkynes.

[00:17:41]So, this only react with terminal alkynes.

[00:17:45]This only react with terminal alkynes.

[00:17:49]This reagent you see here, it react with terminal alkynes only, whereas it doesn't react with alkanes.

[00:17:58]So, with this is a thing that we can use to distinguish between an alkane and what? An alkyne. So, let's take a practical example.

[00:18:10]Let's take a practical example and solve.

[00:18:14]So, when you add we can have that add Tollens reagent, which is a solution that is made up of ammonia and silver nitrate. And then we call it ammoniacal solution or we say ammoniacal solution.

[00:18:29]Are you getting it? Or you can say ammoniacal silver nitrate to suspected alkynes.

[00:18:35]So, what I am going to observe, what I'm going to observe to indicate the presence of a terminal alkyne is that we are going to observe white precipitates.

[00:18:48]White precipitates.

[00:18:51]So, if there is white precipitate formed, if there is a white precipitate formed, I'm going to say alkyne is present.

[00:19:04]And this alkyne that is present is normally terminal alkynes.

[00:19:13]Is terminal alkynes. So, I'm going to say alkyne is what?

[00:19:18]Present. That's exactly what I am going to have.

[00:19:24]And also, when you add Tollens reagent with alkyne, you are going to observe no reaction. So, in summary, Tollens reagent react with alkyne.

[00:19:34]They react with alkyne and they do not react with what?

[00:19:38]Alkene.

[00:19:40]So, they react with alkyne and they cannot react with alkene.

[00:19:44]This is a test that you can use to distinguish between an alkyne and what?

[00:19:49]Alkynes.

[00:19:50]So, for alkynes, we are going to observe a white precipitate.

[00:19:55]That's exactly what you are going to observe.

[00:20:00]Also, you can use this particular reagent, add a solution of ammoniacal cuprous chloride to the suspected alkyne.

[00:20:09]When I use ammoniacal cuprous chloride, if I use ammoniacal cuprous chloride, I can have that.

[00:20:19]So, when you add ammoniacal what?

[00:20:29]Cuprous chloride, which is CuCl, to this, what am I going to have here?

[00:20:37]We are going to This one will give us white. And this particular one is going to give us a red precipitate.

[00:20:44]So, I will have red precipitate.

[00:20:48]I'm going to have a red precipitate, which also indicate that alkyne is present.

[00:20:57]Which also indicate that alkyne is what?

[00:21:00]Is present. That's exactly what I'm equally going to be having.

[00:21:07]So, you see So you see where we are. We We have discussed alkane.

[00:21:13]We have discussed alkene.

[00:21:16]We have discussed alkyne.

[00:21:19]Okay?

[00:21:21]And I want us to know that for alkane KMnO4 does not want to react.

[00:21:28]And sorry, does not react.

[00:21:30]And you know color remover. So which means that the here remains. Here, what happens? KMnO4, which is called the Bayer test. What happens here? Due to the presence of the double bond, the color will change. So there is decolorization here. And here also, there is also what?

[00:21:53]Decolorization. Anything that happens here will also happen in bromine water.

[00:21:59]Here, bromine water, we observe decolorization decolorization. In this case, bromine water, what do we have? No decolorization.

[00:22:10]So this is a summary of how this Bayer test work. This one is called a Bayer test. This one is called bromine water test. So you see how I summarize it. Alkane in the presence of KMnO4 will not react. So that the purple color will remain.

[00:22:30]In the presence of bromine water, the same thing. No decolorization.

[00:22:34]Alkene will react.

[00:22:37]Which means that the purple color will disappear. In the presence of bromine water, the same thing will happen.

[00:22:42]Decolorization will occur. Alkyne KMnO4 the purple color will change, meaning that there is decolorization. And also in the presence of bromine water, there is equally decolorization.

[00:22:58]So I want us to talk about this one, aromatic compounds.

[00:23:06]Aromatic compounds.

[00:23:10]How to determine the functional group of aromatic compounds using bromine water.

[00:23:17]Using bromine water.

[00:23:22]Using bromine water.

[00:23:24]So, if I have a suspected So, for aromatic compounds under bromine water, it will not react. So, we have no decolorization.

[00:23:41]No decolorization.

[00:23:44]So, we are going to observe no decolorization.

[00:23:48]And then your inference should be what?

[00:23:53]Aromatic compound present.

[00:23:58]Aromatic compound present.

[00:24:00]But, if we have a decolorization, it simply means that that talks about aliphatic compounds. Now, one thing you must understand is that aromatic compounds do not change color. They bro- the color of the bromine water cannot change when it is aromatic. But, if it is aliphatic, the color will change. Meaning that for aliphatic, there is a what? Decolorization. And then under aromatic, no decolorization.

[00:24:35]So, this means that for aliphatic, this means that for aliphatic compound, when you treat it with bromine water, when you treat it with bromine water, you are going to observe what?

[00:24:51]Decolorization.

[00:24:56]You observe decolorization.

[00:24:59]So, what happens here is that aromatic in bromine no decolorization and aliphatic in bromine will give us what?

[00:25:13]Decolorization.

[00:25:15]So, we have decolorization here.

[00:25:19]And here there is no decolorization.

[00:25:21]So, you must try to understand each of these.

[00:25:25]Understand it.

[00:25:26]All right, flakes. I would want you to just stop and subscribe to this YouTube channel if you have not subscribed.

[00:25:35]Like the video, comment, and share to your friends.

[00:25:39]I want to stop here and then we continue in the next episode for alkane Sorry, for alkyl halides for amine, amides, sugar, carbohydrate, so forth and so on. So, let us go to the next episode. Thank you and God bless you.