WAEC Chemistry Practical 2026 | Salt Analysis Simplified Step-by-Step

Ajouté : 2026-05-22

[00:00:00]The qualitative analysis this year is very, very interesting. I want us to pay maximum attention to this and thank God you know our channel, we are always showing you the practical, you know, visually. You know, when we see these things, it affirms that these things are true. This is my own opinion, you might not agree with me, it's fine, but as far as I'm concerned about the specimen given for this year, this is what I can infer from what is being given. If they want us to mix it together, which is what we are practically done. So, this is the sample mixed together, all right?

[00:00:34]This is the sample mixed together. So, if you look at the instruction in your various center, you are going to be given all these. But if you are a very smart student, if you what if you have access to this video and you are watching this video, you should know what to do on the day of your exam since I have analyzed this thing here. You should know what to do if you see it in the exam. So, very quickly, let's do the qualitative analysis for this year. So, the first thing they said that C is a mixture of organic inorganic compounds.

[00:01:04]Carry out the following exercises on C.

[00:01:05]Record the observations and identify the gases evolved. State the conclusion you you draw from each from the result of each test. Roman figure 1A now, look at that. So, this is the sample. You are not going to be told the sample, they are just going to label it C, all right?

[00:01:20]So, this is C as a mixture. So, they said we should put everything in the boiling tube, but I will not put all because I will still need to use this for some analysis. But let's put some reasonable amount in. So, look at that.

[00:01:36]They said we should put in our boiling tube. Let me put some other so that we can have a quite number of reactions.

[00:01:48]All right.

[00:01:49]So, they said put C. Did you see that now? Put C, all of C in the boiling tube and add about 15 cm. I will just use my discretion to add 15 cm of HNO3, not water now, HNO3. So, this is my HNO3 prepared. Now, look at this.

[00:02:06]Look at the reaction.

[00:02:08]Can you see?

[00:02:11]Let me test I want to test the gas with my blue litmus paper. Let me see what happens.

[00:02:18]As the gas is coming out, let me see what happens.

[00:02:21]Because there is an effervescence. You can see that effervescence, that bubbling. Let me add some Ah, it's already turning. Let me add You can see it.

[00:02:32]You can see the gas. Did you see?

[00:02:35]Can you hear it? Me, I can hear even the gas. You might not hear, but look at that.

[00:02:40]There is an effervescence, all right?

[00:02:42]I'm trying to test the gas. Actually, I'm supposed to test it with the tube.

[00:02:46]But, let's see.

[00:02:48]Look at the paper. Can you see? It's turning the paper red. Can you see? Look at the gas. It's turning the paper red.

[00:02:54]Let me moist it again for it to be clearer.

[00:02:58]All right. It's turning the paper red.

[00:03:01]Let me moist it.

[00:03:03]Look at that.

[00:03:04]Did you see?

[00:03:06]That means the gas that is coming out is turning blue litmus paper to what? To red. All right. Let me leave that. Let me record. I want to be recording as we are getting it. So, put all of samples. So, please follow the Roman figure now. Look at that. A Roman figure one.

[00:03:24]All right. The sample C in what? In solid. Please don't forget all these things. They are marked for it. C plus what? C is solid form plus what? HNO3 in the aqueous form because this is diluted already. What did I SAY? THE FIRST thing is effervescence occur.

[00:03:44]Um anytime effervescence occur like that, what they are trying you to tell you is that a gas is running out. I don't know the gas anyway, but a gas is running out. But, I will I will show you a trick. I love this particular is very interesting and I want us to pay attention. So, I can record that effervescence occur.

[00:04:02]Effervescence, all right? Occur with what? With an evolution of gas that a gas that is what? Colorless, because I didn't see any colorless and odorless and odorless which turn They didn't ask me to put it what it is. I just added that it can be asked that way. Which Which turn blue litmus paper.

[00:04:43]All right?

[00:04:44]To red. I have to record everything I saw. There's an evolution of gas, all right? There's an evolution. You can see.

[00:04:53]Can you see? Can you see? It's still reacting. Can you see? Can you see?

[00:04:57]Can you see the bubbling in the effervescence? It's still reacting. So, if there is an effervescence now, look at what I want to infer here. If this is an acid, all right? HNO3 is an acid. If I add an acid to a sample, from my chemistry knowledge, even as a student, you should know THAT IF I ADD acid to a substance and there is an effervescence, the probability that that substance there is a trioxocarbonate there is very high. Because one of the chemical properties of acid is that when acid react with any trioxocarbonate, it's going to liberate salt, water, and CO2 gas. Did you get that now? SO, IF I ADD ACID TO A SUBSTANCE AND I'M SEEING the evolution of a gas, the probability that there is a trioxocarbonate in that very particular SAMPLE IS HIGH. WHY? BECAUSE OF THIS IS an acid. And you can see it's still reacting.

[00:05:50]Look at it. Can you see it? Can you see the gases bubbling? I I want to believe you can see it from there. So, I can infer that my CO3 2- or HCO3- is present.

[00:06:07]I can infer. This are trioxocarbonate.

[00:06:09]carbonate. So, FOR ME TO HAVE ADDED acid to a substance and there's an evolution of a gas, the probability that there's a trioxocarbonate. So, it could be this, it could be that. This is a trioxocarbonate, this is a trioxocarbonate. It's possible that they are present. It's very possible because of the This is an acid. I want to believe that is clear. UNLIKE IF THEY WANT US to test for the They can say we should pass the gas into lime water, then we'll know if it is CO2, but they didn't ask us that. And and I don't think they'll be asking us to pass the gas into into calcium hydroxide lime water for us to see the milky color. I'M NOT SURE. BUT JUST SIMPLE PRACTICAL. UM, you know, an acid is being added to a substance, there's an effervescence, then the probability that there's a trioxocarbonate here is high. That's just a simple test as a student. So, this or this is likely to be present.

[00:07:01]And they now said that another less colorless and odorless which turns blue litmus paper red. So, if it turn blue litmus paper red, it means that the gas liberated is what is acidic.

[00:07:17]That's just it. Simple test.

[00:07:20]Just simple test. That's all. Just a simple test. The next thing they asked us to do, let's move on. The next thing they asked us to do they said, "Stir well and filter. Keep the filtrate and the residue." So, I want to filter now.

[00:07:33]So, this is my filter paper. Let me leave this first. Just simple test.

[00:07:39]This is my filter paper, then I'll fold my filter paper.

[00:07:44]All right?

[00:07:45]Then this is my funnel. Look at that.

[00:07:55]Then I'll put it here to filter.

[00:07:59]So everything I can just shake. Look at that. Can you see?

[00:08:04]Look at this now.

[00:08:05]When I leave on standing, they can ask you to leave it on standing.

[00:08:11]They can ask us to leave it on standing.

[00:08:14]If we leave on standing, let's assume they said "Stir well, dilute HNO3 and and and they can just do something like this and allow to stand."

[00:08:32]Did you see that? And allow to stand, then filter.

[00:08:37]Then filter.

[00:08:40]Then filter.

[00:08:41]Allow to stand, just an example. Then then they can say filter.

[00:08:47]Stir well and filter.

[00:08:49]Allow to stand, comma, allow to stand, stir. I'm just well and filter. All right? It's possible. So put all of C in a boiling tube and add about 15 cm³ of dilute HNO3 and allow to stand. Did you see?

[00:09:08]And allow to stand. Can you see? When it was allowed to stand, what happens? Part of the mixture, did you see that? Part of the mixture dissolved.

[00:09:16]All right? Part of the mixture dissolved, while part did not dissolve.

[00:09:20]You can see a clear solution up. Did you see that? While there's another residue down, which means that part of the solution dissolved forming a colorless Did you see that? While the some insoluble residue remain at the bottom. So I can say plus standing, plus allow to stand. I'm just giving So, when I allow to stand, what after part of the mixture dissolved, all right?

[00:09:55]And some part formed an insoluble insoluble particles at the bottom at the bottom of the boiling boiling tube.

[00:10:21]Did you see that? Part of the mixture dissolved, all right? While part did not dissolve. SO, IF SOME PART DID NOT DISSOLVE, it means that there's an insoluble salt here. Because if there is no insoluble substance there, everything should dissolve. Did you get it? I can just infer, just like that. Insoluble insoluble salt present.

[00:10:46]Insoluble salt present. Did you see that? Then they they can now say, then filter. So, let's filter now.

[00:10:54]So, this are probability of what can be given.

[00:10:58]So, they ask us to filter.

[00:11:02]Let's filter now.

[00:11:14]Let's filter.

[00:11:16]If you notice something, look at the filtrate, a clear solution. Can you see?

[00:11:21]On filtering we have a colorless filtrate, right?

[00:11:26]We have a colorless filtrate, and if you see I have a white residue. A colorless filtrate, did you see that? And a white residue. Meaning that the salt Why is this one going down? Meaning there is a compound that is soluble here. That's why you are seeing it go down the filtrate. And there is a compound when I added my HNO3, it means some compounds are formed. One is soluble, one is not soluble. Why?

[00:11:52]Because the one that is soluble go down with the filter paper, while the one that is insoluble is actually up. I can still record something there. Something there. Very important. I can record something there.

[00:12:05]I can record something there. So, what can I record there? Plus filter.

[00:12:10]Plus filter. When I filtered, what did I have? A colorless a colorless filtrate. [laughter] And what?

[00:12:23]A white residue.

[00:12:27]Did you see that? A colorless filtrate and a white residue. It means that that solution I filtered, I can just say the solution is a mixture of soluble and what? Insoluble salt or compound, ANYONE.

[00:12:53]WHY DID I SAY THAT? BECAUSE IMMEDIATELY I I added HNO3, DID YOU SEE? IMMEDIATELY I ADDED HNO3, there is a clear solution of there is another residue down. When I filtered, I have a clear solution. Look at that. I have a clear solution, which means that the one that is soluble goes down the filter paper, while the one that is not because HNO3 have created a reaction. That is it.

[00:13:16]HNO3 have created a reaction. So, it means this one is soluble. That's why it's going down the filter paper. And there is one on top of the filter paper.

[00:13:24]Come and see it. Maybe you bring our camera. Did you see? Look at it. Can you see it now? Look at this one. This is the white residue while this one is the what? Is the colorless filtrate.

[00:13:34]Meaning, this one is soluble, this one is what? Insoluble.

[00:13:38]I want to believe this is clear. I just want us to follow me.

[00:13:42]Then what is the next one? Let's move on. What is the next one? Keep the filtrate and the residue. DID YOU SEE THAT? DIVIDE THE FILTRATE INTO three portions. So, we're going to divide that into Then I say Roman figure two now.

[00:13:55]ROMAN FIGURE TWO. PLEASE FOLLOW THE NUMBERING. Roman figure two. They said, "To the first portion of the filtrate, test with litmus paper." All right? And add sodium and add ammonia in drop and in excess. Very simple. Very simple.

[00:14:14]Let me bring this out. Let me just put it here.

[00:14:17]Probably to continue the filtration.

[00:14:20]So, this is the filtrate now. This is the first portion. Let me have the first portion.

[00:14:31]So, this is the first portion of the filtrate. Let me keep it safe.

[00:14:36]So, this is the first portion of the filtrate, right? This is the first portion. Don't worry. So, let me take my dropper. They said we should add NH3.

[00:14:46]NH3. So, that's ammonia. So, let me add SOME AMMONIA IN DROP and in excess.

[00:14:53]Please, take note of that. In drop and in excess. Take note of that. In drop and in excess. So, let's see.

[00:15:02]In drop, let's see. In drop.

[00:15:06]Look at that. In drop.

[00:15:10]Did you see? What do you have in drop?

[00:15:12]Something like a chalk. In drop, that's a white chalky precipitate. In drop.

[00:15:18]Did you see that?

[00:15:21]Can you see? Like I grinded chalk and put inside. That's the meaning. Can I get to see that very well? I want to show I want to be sure you are seeing it.

[00:15:29]White, chalky, precipitate in drop.

[00:15:33]Then, let me add it in excess so that we record the two now.

[00:15:38]In excess now.

[00:15:42]Let's add it in excess.

[00:15:46]Let's add it in excess.

[00:15:48]Let me put it here. So that I can have some reasonable amount of this in excess.

[00:15:56]Let's come here. Look at that. Let's see.

[00:15:59]I'll bring it out.

[00:16:01]Let's put it they said in excess.

[00:16:05]Look at that. Let me add some again.

[00:16:11]I'm trying to add it in excess as instructed. Look at that.

[00:16:21]Let's add it in excess. When they said excess, please, because we want to see something. So, let's bring it up again.

[00:16:27]Look at that. It's insoluble. Look at Can you see the precipitate? Can you see that?

[00:16:33]Look at the precipitate. Can you see?

[00:16:35]Very, very obvious. Can you see that?

[00:16:38]Can you see that? The precipitate did not dissolve. You can see the way they are just jogging and running up and down in the solution. All right, let's record now.

[00:16:47]Just follow the steps. Look at that. So, we can now add first portion first portion All right, to the first portion of THE FILTRATE OH, TEST WITH LITMUS PAPER.

[00:17:00]WE'LL DO THAT so that I can record it.

[00:17:02]Test with plus litmus paper. I will record that.

[00:17:06]I'll record that. Don't worry. I will use another one. Then, plus plus what? Ammonia.

[00:17:15]In what? In drop. What did it GIVE US?

[00:17:17]WE'LL RECORD THIS one later. We'll test with litmus paper later. In drop, we have what? A white chalky precipitate.

[00:17:28]If you have white chalky precipitate, two ions are likely to be there, which is the calcium two ion and the lead two ion is likely to be present because you have this white chalky behavior. But, when we added it in excess, what happens? The precipitate, all right?

[00:17:49]Remain insoluble.

[00:17:54]Insoluble in excess. And if it's insoluble in excess, there's only one matter that used to behave like that. That is the lead is what is present.

[00:18:06]Are we together here?

[00:18:07]Are we still here? All right. Now, let's add the second portion now. Don't forget we are still with the filtrate.

[00:18:15]All right, we are still with the filtrate. Let's add second portion of the filtrate. Then, I'll now test with litmus paper so that I can record that one.

[00:18:27]So, this is it.

[00:18:29]Second portion. Okay, let me test with filtrate here. This is blue.

[00:18:34]This is red. Let's quickly do that so that we can record something. It's not changing with this. It's not changing.

[00:18:40]Let's use blue now.

[00:18:42]Let's use blue.

[00:18:45]All right.

[00:18:47]Look at that.

[00:18:49]It's changing it to red. So, let's quickly write that. Then, we can now move on with our filtrate and all. So, first portion plus litmus paper changes blue litmus, right? Red. So, we can say the solution is acidic. That is that filtrate is acidic.

[00:19:12]That's meaning The filtrate is acidic.

[00:19:14]So, we have done white chalky precipitate remain insoluble. Then, we go to Roman figure three now. To the second portion of the filtrate, add sodium hydroxide in drop and in excess. So, three That's second portion plus sodium hydroxide in drop and what? And excess. Let's see what it will give us. So, quickly, let's add that now.

[00:19:46]So, this is it. This is another filtrate we have actually added here. So, let's see sodium hydroxide. Where is our sodium hydroxide? I hope we still have some few sodium hydroxide. All right.

[00:19:57]This sodium hydroxide in drop, then in excess. So, let's see in drop.

[00:20:05]So, let's see it in drop. Look at that.

[00:20:07]Drop and in excess. Look at that.

[00:20:12]Did you see in drop and in excess? Did you see that?

[00:20:16]This is in drop. We are still seeing a white chalky in drop. Look at that.

[00:20:21]A white chalky in drop. Did you see?

[00:20:23]Let's now add it in excess now.

[00:20:26]Let me put it here again so that we can Okay, let me put it here. Let me do this. Let me put this here. Then, look at the one for sodium hydroxide. I want to put it here so that we can add excess of the sodium hydroxide. So, let's see.

[00:20:46]You can see the the white chalky is now out fully.

[00:20:53]I have to put it in excess.

[00:21:05]In excess.

[00:21:07]Let it be in excess so that we can record something.

[00:21:15]In excess, please take your time. Take your time.

[00:21:19]Don't be in an haste. Look at this. Let me bring it up. You do see it's beginning to dissolve the precipitate.

[00:21:26]Let's add more. That's why they said in excess.

[00:21:30]Let's have it in excess.

[00:21:34]Look at that.

[00:21:36]Can you see a clear solution now? In excess it dissolved. Let's add more then we can now record our values.

[00:21:48]I think that should be okay. Look at that. It dissolves it. Did you see? In excess sodium hydroxide dissolved. So it dissolved the precipitate. So let's come here now. So second portion plus in drop we still saw a white chalky precipitate.

[00:22:09]And if it is that, we can still infer that our calcium So to the third portion now of the filtrate, look at that.

[00:22:18]To the third portion add dilute HCl. So let me first of all add the filtrate.

[00:22:23]This is the third portion.

[00:22:26]This is the third portion.

[00:22:30]All right, this is the third portion of the filtrate.

[00:22:33]Then add dilute HCl. This HCl.

[00:22:36]Let's add this.

[00:22:39]Let's add this.

[00:22:43]Look at that.

[00:22:45]A white precipitate. Did you see?

[00:22:47]A white precipitate. So they now say we should heat it. So let me [clears throat] heat it so that we can just write the So let's go to heating.

[00:22:57]Now look at it. Let's heat it.

[00:23:06]>> Can you see that?

[00:23:08]The white precipitate is disappearing.

[00:23:11]Did you see that?

[00:23:20]So, the white precipitate is disappearing on eating.

[00:23:30]Did you see?

[00:23:32]So, white precipitate is disappearing on eating. Then, when we cool, it will reappear. That's just what I want us to see here.

[00:23:43]Look at that. Did you see the white precipitate has disappeared on eating?

[00:23:47]Did you see it? That's just what I want us to see there. So, the fourth one, we have fourth portion plus what?

[00:23:59]Plus dilute HCl in aqueous. What happened? We have a white precipitate.

[00:24:09]Is that not? Then, plus heat.

[00:24:12]Plus heat, what happens? Precipitate dissolved.

[00:24:20]Precipitate dissolved on eating.

[00:24:24]All right? And reappear >> [clears throat] >> and reappear on cooling.

[00:24:32]So, precipitate dissolves on eating and reappear on cooling. We are going to have Pb2+ >> [clears throat] >> present.

[00:24:42]Did you get that now? So, the last one now, which is B Roman figure one, as we call it. So, this are just what we can be asked to to do.

[00:24:51]So, this is our what?

[00:24:54]Bring it closer.

[00:24:56]So, this is the They may ask us to put it in the test tube. This is our residue now.

[00:25:01]All right. So that's the iodine now being tested on the residue.

[00:25:07]So as you can see that blue black. Did you see it? You see that blue black? So they can ask you to put the residue in a test tube or in a boiling pot and put iodine. You're still going to get the same thing.

[00:25:19]Did you get that now?

[00:25:20]B1 now that's the residue plus what? Plus iodine.

[00:25:27]Plus iodine solution.

[00:25:29]So we have blue blue black color observed.

[00:25:39]Then we can now say starch is what? Is present.

[00:25:43]So what is that?

[00:25:45]So and that's the reason why most times they will allow the starch to dry up before we add iodine to be effective.

[00:25:51]But if you add iodine, it's going to change to blue black. And that's that's just what they can ask us to look for. So I wish you success in your exam. Thank you. Subscribe to this channel. Click on the notification bell so that when we upload any video, you are going to know.

[00:26:05]So that's the qualitative analysis. God bless you. Thank you.