INORGANIC ANALYSIS 1

Added: 2026-05-12

[00:00:03]So today yesterday I actually tried to look at the chemistry of the onions. How do we what chemistry is there and which tests are we going to use to be able to analyze the onions to analyze the onions very well. Then today I'm going to look at the identification of the kions. It's going to be the last the second last segment of this identification of the kions and obviously yesterday I went ahead and gave you people a scope of the kions that are necessary for our for our study. I went ahead and we said we had classified those into two major categories. We classified them under transition.

[00:01:00]We looked at the transition the transition metal cations. Those ones there included included the likes of ion 2 included the likes of ion 3s.

[00:01:14]We had cobalt 2.

[00:01:18]We had nickel 2.

[00:01:22]We had manganese two ions. We had the chromium three ions. We had the copper two ions. And then the zinc, this zinc 2 ion here is actually not a transition for it is a non a non transition metal metal cation.

[00:01:41]However, when you're studying the transition elements, it is usually not called a typical transition metal metal cation. Why? Because for it usually what happens is that is that it has the reason why transition metal cations are called so is because they have partially filled B sub energy levels. But now this one here the these the zinc zinc to ions for it. It has a fully filled d sub energy level in either it is ground state it's neutral atom or in it is it is iron. So it's not really referred to as a typical transition metal cation. So those are the ones that we have under the transition. Then the ones we have under the nonransitions non transition. The N transition here we have the zinc 2 zinc two ions zinc ions we have the aluminium ion we have the lead ion we have the tin ion we have the barium ion we have the nitrate ion nitrate has a charge of1 we have a sulfate sorry what am I even writing root and barium. Then again nitrate supposed to include calcium the calcium then the magnesium the magnesium ion. So these are the nonransition metal cations that we say that we are we are going to look at. Then one thing I highlighted yesterday is that when you look at these transition metal cations, what makes the reason why why we are classifying them as transition and non transition is majorly because these guys here for them they are able to form colored compounds.

[00:03:46]It's one of the characteristics of the transition the transition metal cations for them they in position to form colored compounds and because they can form colored compounds that means that our study of them is really going to be it's going to be easy. It's very easy to study or to identify the transition metal cations because of the presence of color. Okay. If you see something blue can it can can give you an idea or a clue. Okay. Then with this non transition for them they actually they actually have no no color. Okay. So for them usually in appearance they appear as white as solutions appear as appear as colorless. So your study of the nonransition metal cations is needs to be a little bit more technical compared to the ones of the transition the transition metal cations. So yesterday I began by saying that the tests that we do to determine or to identify the nature of these guys are broadly classified into two. And the first one I'm going to start with is going to be the preliminary tests preliminary preiminary tests. And I said yesterday that these preliminary tests for them what they do is that they just give us an idea. they just give us a clue on the cation that is present there. Okay.

[00:05:15]Meanwhile, for the confirmatory test for them, they give us an idea beyond reasonable doubt. In other words, they confirm to us beyond reasonable doubt that this particular ion is present. So I went ahead and say that these preliminary tests can be summarized into about three. One of them is going to be the appearance of the appearance of the sample.

[00:05:40]appearance of of the sample. The second one is going to be on the effect of heat on that particular sample. The effect of heat on that on that sample. The next one is going to be is going to involve an aspect of solubility.

[00:05:58]How does that thing dissolve in dissolve in water? Then the fourth one here is going to be the effect of an alkaline effect on sodium hydroxide or ammonia ammonia solution.

[00:06:18]So those are the four major preliminary tests that we are going to have in inorganic analysis. These ones here for them they are just going to be giving us a clue or an idea of what is going to be there.

[00:06:31]Please mute your microphones.

[00:06:34]By now, I don't expect us to be struggling with such things like muting the microphones. You again want me to mute the entire class. Okay?

[00:06:44]So, make sure you mute your microphones.

[00:06:49]By now, I don't expect people to attend the class and you just leave your phone just there and you're not even minding about the lesson. I expect guys to exercise certain level of maturity by now. Okay.

[00:07:05]All right. So that is what we looked at.

[00:07:07]So we are going to begin looking at that one by one and after us looking at that one by one we shall be done with the preliminary the preiminary tests. Okay.

[00:07:17]So that is the first thing. So let's start with the appearance of the solid.

[00:07:23]Okay. is the appearance of of the solid the appearance of the solid. Okay, the color of the solid can give us a clue on the ions that that are present. Firstly, that is why I'm going to summarize for you. I'm going to put this in form of a table. Okay, let me have a table here.

[00:07:54]And this table is going to be the color of the solid color of the solid. Then this one here is going to give us the cation that is going to be suspected due to due to that color.

[00:08:09]So the moment you enter the lab and you see a sample there, the moment you look at that sample, that color is supposed to give you already chemistry about the cation that you think is going to be suspected. Okay? So the first thing that I want the first color I would like us to note is going to be white. A white solid.

[00:08:30]When you see a white solid presented to you, one thing is supposed to run into your mind that the salt that we have been given is falling under the category of the non-transition met.

[00:08:43]The nonransition metal cations. Remember we say that for them they are white in color.

[00:08:49]The nonransition metal cations. So the moment you see something which is white on your table, your mind should immediately run to the non-transition metal cations which are there zinc, aluminium, lead, tin, barium, calcium and and magnesium. So that is the first thing the color of of the solid white then the next thing that you should do if at all you have seen something which is colored. Okay, if I have seen a colored solid now there I'm not minding about the color. If I've seen a colored solid then I mean I I I should I should be able to know that something that have been given is actually a transition a transition metal cation. Okay. Now let us go into the details of the color.

[00:09:35]First the colors that we have the first color we have here is green. If I see a green a green solid what do I expect?

[00:09:46]There are three transition metal cations that can give us something which is green. There about four of one of them is the chromium 3 ion. The other one is going to be the nickel 2 ion. The other one is going to be the copper 2 ion. And then the other one is going to be the iron 3 ion 2 sorry ion 2 ion to ion. So those three there are the ones that usually appear as green and they form the max the biggest number of the transition cations. most of them appear appear green. Okay. So, how do you go about with the things? You make sure that this summary here after us making the summary, you go ahead and have that summary on at least a sheet of paper.

[00:10:30]Everywhere you go in the school compound, your duty will be to check green solids here. It will be maybe copper 2, iron 2, nickel 2, and chromium 3. You note that down, you keep on reading it, and by the end of the day, those things would have become normal in your brain. you just reach a point whereby you just know them. Okay. Then if I see a blue solid, a solid that is blue, that is going to be copper copper 2. So most of the everything that you're going to see that is going to appear blue, that is going to be copper copper 2. So you're going to suspect a copper 2 a copper 2 ion.

[00:11:08]Then number four, we have something that is pink or red.

[00:11:16]that is either pink or or red. Something that is pink or red here is going to be the mang the manganese ion and then the cobalt the cobalt iron those ones can either appear pink or red but more so this manganese iron here for it it's the one that appears so much of pink sometimes it is very pale pink such that it can even appear as as white the students that did UNEB last year 2025 that is what they brought in practical they mixed the mag the manganese iron with a white with a trans with a non transition a non transition metal cation. So the entire thing look like it was a white look like it was a white salt. So that is how how it is. So if something is appearing pink or red suspect the manganese manganese ion then if something is appearing if something is appearing brown or yellow okay brown or or yellow. Now these colors here in chemistry they usually give allowance for people that have eye issues because not everybody is in position to tell color color very well. Okay. Somebody may see something which is yellow as brown or something which is brown as yellow. So any of the two is correct. If I'm having something that is brown or yellow the cation that I'm going to suspect is going to be iron 3.

[00:12:42]It's going to be iron 3. So that is that. So the color of the solid that you have been given should give you a clue.

[00:12:48]The moment you go on your table and you see a green solid just know I either have chromium, nickel, copper 2 and then iron 2. Okay. If I see something blue, I know it is copper 2. I see something brown, it is iron 3. I see something red, it is going to be manganese 2 ions.

[00:13:08]So that is the first hierarchy. The appearance of the solid can give you a clue on what is on what is there. Okay.

[00:13:17]So that is the first part. I hope members are okay with that. If you're fine, give me thumbs up as a reaction.

[00:13:25]Then if you if we can proceed, give me a thumbs up. If you are not fine, give me a thumbs down.

[00:13:38]Okay, let me see people reacting.

[00:13:44]And sometimes you don't have to to wait for me to tell you to react. Like now when I finish that area of the appearance of the solid, sometimes I can say is that okay? You can just put those reaction those reaction emojis. Okay? So that we are together. So the color of the solid is very is very key. Then the next preliminary test that we are always going to have that is going to be part B is going to be the effect of heat.

[00:14:12]Effect of heat on a given on a given sample. So when I heat a particular sample there is there are certain things that we are going to deduce out of it.

[00:14:22]Okay. So the effect of heat can also give us a clue on what is on what is present. So when you go ahead in the laboratory and you get a specific sample okay of the salt that you have been given and you're going to the Bansen burner or to the charcoal stove depending on your school and you're going to the heat source there are four things that your your mind is supposed to be thinking about. The first thing that your mind is supposed to be thinking about is going to be the gases that are evolved. Okay, gases that that are evolved. So the gases that are involved have to give you a clue on what is there. The second thing you need to think about is going to be the residue.

[00:15:05]What residue am I going to get after me heating this this sample?

[00:15:11]The residue. Okay. The third thing you're supposed to think about is going to be water vapor given water vapor given off given given off. So as you take your thing to heat there are three things that you're supposed to be thinking about which gases have been evolved which residue has been has remained and is there any water vapor that is that is given off okay so these are the three things that have to come to your mind whenever you're going to the heat source whenever you're going to to a bunen burner now I want us to note that the gases that are evolved these ones here usually give us a clue on the onion that is present.

[00:15:56]The annion that is present is is the gas that is evolved is due to an onion that is present in that in that salt and then the residue that is formed is due to a cation that is that is present. So the gases that are evolved during heating give us a clue on the onion that is present. The residue that is going to be left after heating is going to also give us a clue on the cation that is that is present. Okay. So we are going to start looking at them one by one. This is going to be Roman one. This is going to be Roman 2. And then that is going to be Roman Roman 3. So Roman one I want us to understand the gases involved.

[00:16:41]Gases gases evolved. Okay. Gases evolved. So whenever a gas is evolved, you need to be in position to clearly identify that gas. You need to be in position to clearly identify that gas.

[00:16:56]And a gas is usually clearly identified by by about four parameters. The first parameter of identification of a gas is going to be on it smell. Okay? Sometimes you can include the smell. There are some gases that have a really terrible smell that they can be identified by that smell. Then sometimes also the color of the the color of the gas. Then nextly the effect of that gas on litmass paper. What is the effect of that gas on litmus on litmass paper? Then lastly when you're identifying a gas you can also give us its confirmatory test if there is the confirmatory test of of a given gas. So those are the four things that should come into your mind when I want to identify a gas. So gases should be identified by their color, their smell, the effect on litmus paper plus a given confirmatory confirmatory test and all those things have to be captured within your your observation. So let me give you a sample observations that we can write down and then the gases that call for those those observations. So I'm having observation there. Then I'm having I'm having deduction.

[00:18:18]I'm having I'm having deduction. Okay.

[00:18:21]So let us assume that there is a gas that has been evolved. Okay. So here let me say that here we are having carbon dioxide gas. The reduction is carbon dioxide gas has been has been evolved.

[00:18:35]And which onion is going to give us carbon dioxide gas from the things that we have from the information the onions that we have we we actually came up with it is going to be a carbonate. So if carbon dioxide gas is evolved there are four means a carbonate is is present.

[00:18:53]Okay. So how do we write up that observation there?

[00:19:09]Excuse me for a small Okay.

[00:20:48]Right.

[00:20:52]Sorry for that. I just had something a little bit urgent to to attend to.

[00:21:00]We have something small to to I had something small to attend to. So I'm saying that assuming that carbon dioxide gas has been evolved, how are we going to write our observation? Okay. So we are going to first of all identify the color of that of that gas. So here we are going to say that it is a colorless gas. Obviously carbon dioxide is a colorless a colorless gas. Okay. So that is a colorless gas. So after us identifying the color of that gas we write down it effect on lit on litmass paper. So we are going to say colorless gas that turns blue lit mass paper red.

[00:21:38]Colorless gas that turns blue mass paper red.

[00:21:45]Turns blue mass paper red. That is the effect of carbon dioxide gas on it mass paper. Then after that we also write it is effect. We also write it is confirmatory test. The confirmatory test of carbon dioxide is that it turns lime water lime water milky. So we are going to say colorless gas that turns blue it mass paper red and lime water and lime water milk colorless gas that turns blue mass paper red and also lime water lime water milk.

[00:22:23]So there we have properly identified that gas and you can confidently say that that is carbon dioxide gas that has been evolved and therefore it is and therefore it is it is it is actually a carbonate that is suspected to be present that is one gas. Okay I want to give for all the gases that we are most likely to have. What if the gas we are going to have is is a sulfate sorry is is sulfur dioxide gas. Sulfur dioxide gas. Okay, that sulfur dioxide gas confirms the presence of what? A sulfate sulfate ion. So the sulfate ion is coming from sulfur dioxide gas. So how do we identify that gas? That gas is also a colorless colorless gas.

[00:23:13]Okay. And what is its effect on lit mass paper? It turns blue lit mass paper blue mass paper red. So we are going to say colorless gas that turns blue lit mass paper red.

[00:23:30]It turns blue mass paper red.

[00:23:33]Okay. And after turning blue it mass paper red. What is the confirmatory test of that of that gas? The confirmatory test is that it turns and turns acidified.

[00:23:52]It turns acidified potassium dromate turns acidified potassium dromate from orange from orange to green. That is the confirmatory test of sulfur dioxide gas for it turns acidified potassium dromate from orange to from orange to to green.

[00:24:19]So in that way we have been in position to clearly identify that gas a colorless gas that turns blue mass paper red its effect on lit mass paper and then it's confirmatory it is confirmatory test.

[00:24:32]Therefore it means sulfur dioxide gas has been evolved and is originating from from a sulfate. Okay. So that is that what if we are having we are having another gas most likely what if we are having nitrogen dioxide gas. Okay nitrogen dioxide gas. And that means that this nitrogen dioxide gas is coming from a nitrate a nitrate ion. Okay. So how are we going to write the observation? What is the color of nitrogen dioxide gas? Nitrogen dioxide gas is simply reddish brown reddish brown fumes. Okay, of which they are reddish brown reddish brown fumes. What is it is effect on litmas paper that turns blue litmas paper red.

[00:25:24]Turns blue lit mass paper red.

[00:25:30]turns blue mass paper blue mass paper red. We don't have a serious confirmatory test for it for now. So that means nitrogen dioxide gas has been evolved and therefore nitrate is suspected to be to be present. Okay. So that is basically that. So those are the sample gases that that we have and the onions that those gases are coming are coming from. Okay. So that is how we write our observations on the gas that has been evolved.

[00:26:06]Okay.

[00:26:13]All right. Now somebody's saying that when you see a colorless gas, what do I base on to do which confirmatory test? Or I do both for carbon dioxide and sulfur and sulfur dioxide. Okay. Now there is how your practicals are going to be. Now most of the times this these are confirmatory tests of the gases that are evolved. You don't always write them before you confirming the onion that is there. Okay. So usually those confirmatory tests for the purposes of exams usually we write them usually the confirmatory tests are written we write them after confirming we write them after confirming the cation and the onion present the cation and the onions that are that are present. So the way I'm going to train you people is that we first of all start by doing the other tests and after us doing the other tests and we confirm that this kion and this onion are present then we go back and fill in the space that we had left for the effect of heat. So most of the times even this effect of heat you can do it theoretically from your head. Okay. But after you confirming the kayion and the onion, you can go ahead and hit. And as you're hitting, you should be suspecting or you should have a clue on what you're expecting expecting to see. Okay, that is basically what happens.

[00:27:49]So if I have already confirmed the presence of maybe a sulfate, so when I'm going to heat in my mind, I should already be knowing that sulfur dioxide gas is going to be absorbed. So if I'm having some acidified potacham dromate near, I can bring it there and you're going to see the change taking taking place. Okay. So that is basically how it's going to be done. So in the next lessons we are going to I'm going to show you how you're going to be manipulating this work to come up with with right results.

[00:28:20]So those are the gases and the sample observations and deductions that that we can have. So the gases evolved at something which is very key when we are doing when we are heating. Okay that is part A. Part B the gases evolved is part is Roman one.

[00:28:38]Okay Roman two is going to be on the residue.

[00:28:50]The residues I'm seeing somebody's hand is up. People's hands are up. Let me start with harmony. Please unmute.

[00:29:00]>> Good afternoon sir.

[00:29:02]>> Good afternoon.

[00:29:03]>> So my inquiry is at school when we were doing this specific practicals we also encountered ammonium. How come here we're not covering it.

[00:29:11]>> Okay. Now I told you guys the scope of what we are what we are going to be studying. Okay. And I'm actually looking at the scoop. I don't know whether your teacher has told you that the ammonium ion is present is is actually available in the scope but it's actually not there in the scope of what you're going to study. So maybe you were just covering it for the purposes of knowing general information. Okay. But the ammonium ion is not there.

[00:29:40]Is that understood?

[00:29:42]>> Yes sir.

[00:29:43]>> Okay. So the ammonium ion is not there but maybe the teacher was just trying to cover it up. You know sometimes when you're in the laboratory and maybe something may be missing. So sometimes you can decide to just mix a salt that is having an ammonium ion to just try to show students the concept. Okay. But in actual sense the ammonium ion is not necessary. But you knowing it has no effect on your chemistry your chemistry knowledge. For me I'm just covering what is really very very necessary.

[00:30:14]In case of anything, you can still add on.

[00:30:18]The gas that gives us a pungent chalking smell is usually sulfur dioxide gas or ammonia gas. Okay? But you can include it there if you identifying sulfur dioxide gas or you may not include it there. There is usually no penalty for that.

[00:30:35]But usually the gas that is so much identified with it is smell is ammonia gas. Okay? So it is ammonia gas that has that is so much identified by it smell.

[00:30:46]When you smell ammonia gas that smell there is very unique for only that particular gas.

[00:30:53]So I don't know whether there other questions here.

[00:31:01]Okay. So let's go to the next thing on the residue. So after me hitting that specific substance or that specific salt I am going to get a residue. Okay. And that residue we said it gives us a clue on the cation that is on the cation that is present. Okay. So, usually what chemistry happens during heating. The chemistry that happens during heating is that you're going to be given a certain a certain salt. Okay? Or a mixture of a mixture of salts. And when you heat that salt, that salt is decomposed on heating to give us an oxide. Okay? plus a given given gas. The oxide that is going to be given off is going to consist of the residue and we say that this residue gives us a clue on the cation that is present and then the gas that is going to be evolved is going to give us a clue on the onion that is that is present. So usually these residues here that we are going to encounter are usually going to be oxides that are coming from the decomposition of of the salt. Okay. So we go ahead and have sample we need to get sample sample observations plus their deductions for most of the oxides in these salts that we are looking at.

[00:32:21]So one of them. So let me have the observation here and then the deduction observation plus plus the deduction.

[00:32:41]Okay. Let me start by us having a black solid a black a black solid or a black residue.

[00:32:50]Black. So you have heated your solid and at the end of the day you have ended up getting a black a black residue. Which oxides are those that appear black from the scope of whatever we whatever we are studying. The oxide that appears black is usually copper 2 oxide. Okay. We have iron 2 oxide, we have nickel 2 oxide, we have manganese, manganese oxide. those oxides usually for them they appear as black. So the moment you see a black residue it means that those oxides any of those oxides has been has been formed and then you you therefore deduct and say that is possible that the copper 2 ion is suspected to be present. Iron 2 is suspected to be present. Nickel 2 is suspected to be present or manganese manganese ion is suspected to be to be present. That is if you have a black a black residue then what if I have uh this is one the black residue two if I'm having a white solid a white residue white a white residue so heated that thing and I get a white residue which oxides are purely white from the scope of what we are looking at the oxides that are white. One of them is aluminium aluminium oxide. The other one is calcium calcium oxide. The other one is magnesium magnesium oxides. Those are the only oxides that appear that appear white. So therefore we deduce the cations that we suspect to be present by having the aluminium ion, theium ion and then the magnesium the magnesium ion.

[00:34:45]Okay. So those are the residues that would usually appear appear white that would give us that appear white and those are the cations that they are coming from.

[00:34:56]Okay. Then another likely observation that would always encounter number three is that you'll always get a yellow residue when hot.

[00:35:06]Yellow residue when hot when hot and turns white on cooling.

[00:35:16]Yellow residue when hot and turns white on on cooling. The yellow residue when hot and turns white on cooling. That one is usually zinc oxide. Okay, it is the only residue that is yellow when hot and turns white on cooling. That means that the cation that is suspected to be present is going to be the zinc to zinc to iron. Okay, yellow residue when hot and turns white on on cooling. Okay.

[00:35:48]Then the last one here we are most likely to encounter is going to be a reddish brown residue when hot.

[00:36:08]reddish brown residue when hot and turns yellow on cooling and turns yellow reddish brown residue when hot and turns yellow on cooling. The only oxide that shows that behavior is going to be lead oxide which is a solid. Okay, therefore that means that the lead ion can be suspected to be to be present. So that one there covers most of the kions that that we have looked at.

[00:36:49]So those are the sample observations and anductions.

[00:37:01]Okay. So I hope that part is clear. So you need to go back and sit down and master in other words in a humble way.

[00:37:10]Go ahead and sit down and know those oxides which are black. Know those oxides which are white. Know that oxide which is yellow when hot and turns white on cooling. Then know that oxide which is reddish brown when hot and turns yellow on on cooling.

[00:38:36]Okay. So, I think that is okay.

[00:38:42]W even barium oxide is white. I'd forgotten about barium oxide. Thank you for the reminder.

[00:38:48]So, even the barium ion here is also there.

[00:38:52]So, barium oxide is also is also white.

[00:38:56]So that is basically that.

[00:39:01]All right. So that is the issue of the residue. So whenever you're heating, watch up for the gases that are involved. Identify them properly and gives you an idea of the onion. Okay?

[00:39:12]And then when you're heating, you watch up for the you watch up for the for the residue that has been formed and gives you a clue on on the cation. Then the next thing we are going to do is water vapor. So, it's going to be Roman Roman 3.

[00:39:34]So, water vapor there is going to be on Roman on Roman 3. Whenever you're heating, watch out to find out if there is any water vapor that has been that has been given off.

[00:39:54]water vapor that has been given off. So usually some of these salts that we are going to see okay some of these salts that we are going to be given usually some of them are hydrated okay some of them are hydrated meaning that they contain water of crystallization.

[00:40:11]So usually when a hydrated salt is going to be heated, it first of all decomposes to give off. Okay. Usually when these hydrated salts are heated, it is going to give off. It is water of water of crystallization.

[00:40:27]It's going to give off. It is water of crystallization.

[00:40:37]It's going to give off its water of crystallization. Okay. Now that water of crystallization that is has been given off is what is going to appear as vapor and that vapor is going to condense at the cooler parts of the test tube. So whenever you're heating you'll find you'll find the test tube having some condensate that is found around that.

[00:41:00]Okay. So that condensate there is usually water of crystallization that has been given off. Whenever you're recording your observation there for water of crystallization, you have to clearly identify the water. Okay? You have to clearly identify the water because in chemistry not any colorless liquid liquid is is water. So what sample observation get there? The sample observation there is going to be that we are going to have we are going to have a colorless liquid a colorless a colorless liquid we have seen a colorless liquid formed at the cooler ends of the test tube or usually sometimes that liquid can be called a condensate.

[00:41:50]So a carless condensate then from there we need to be in position to identify that condensate very well using it is confirmatory test. So the carless condensate turns and hydras copper to sulfates turns and hydras copper 2 sulfates turns and hydras copper to sulfate from white to blue. from white to blue. Okay.

[00:42:22]So that one there means that there is water of crystalliz there. The way you're now going to write your deduction deduction.

[00:42:34]So the way you're going to write your deduction is that you have now confirmed that that colorless liquid there is water of water of crystallization.

[00:42:45]That is water of crystallization.

[00:42:48]So if that is what of crystallization there are fork it means that what it means that the salt is is hydrated. So the sample we have been given is a hydrated hydrated salt. So that is how you go about with the issue of the water vapor. Obviously when you're heating and you find out that is water vapor you will know it is water. But somebody's going to say why do I need to write this confirmatory test of the confirmator test of water because it is a marking point. Usually that is where the marks are. Okay. So you may not have to ask or to request for copper 2 sulfate but you just write it there and you clearly confirm that that that is water to show that there is water of crystallization that has been that that has been given off. So the salt that we have is a hydrated a hydrated salt. it's a hydrated salt. So basically those are the three things we need to watch out for whenever we are heating heating the given samples that that we have we have to watch out for that. Then yesterday I I I gave somebody asked about texture about texture texture can give you a clue on what is going to be what is there. One of the texture that I used to love using so much is actually a carbonate.

[00:44:10]Okay, most of the carbonates when you examine them in the lab, they actually appear as powders. Okay, most of the carbonates appear as powders. So when you're given a sample and you look at that sample critically, okay, now the problem is that sometimes they mix the things up. They can mix up a salt that is crystallized with a carbonate. But when you observe it clearly and you see that there is some powdery element in it, you can suspect a carbonate to be to be there. But this this one here just remains in your head. You don't write on the paper that because the thing is powdery I think a carbonate is there.

[00:44:48]No, that one there is just the sense that you're going to use in your in your head. Okay. Then if the salt that you have been if the salt you have been given is rough, it is texture. Okay.

[00:45:00]That means that that salt is majorly consisting of of crystals. And because the salt is consisting of crystals, it means that that salt there is hydrated.

[00:45:10]It has water of crystallization. Because what enables a salt to form crystals is that water of crystallization. So if the texture of that salt is rough, just know that that salt is having water of of crystallization. That means that it is a hydrated a hydrated salt. So that is what we have on heating. So the issue of heat can give us a clue on what is what is present.

[00:45:39]The aspect of heat can give us a clue on what is on what is present.

[00:45:46]Hassan is having a question. Please unmute.

[00:45:53]>> Yes. Good afternoon sir. Good afternoon.

[00:45:57]>> So my question is uh for example when we are talking about the observation of the the residue we have black residue and then the deduction we are having we having the copper copper oxides and then you say that you mentioned the oxides which are present then how can we differentiate this specific oxides from the rest for example when they all mixed up how can I know that this is copper oxide this is iron oxide. Uh-huh. Now the issue is what we are saying is that that is a preliminary a preliminary test. It just gives you an idea or a clue. So that idea part of that clue is that it is having a mix up of things.

[00:46:38]Okay. That is why as we are going down to do up to the confirmatory test, it is now what is going to prove to us beyond reasonable doubt that it is copper 2 but not nic 2. So it is part of the preliminary tests or it is in the preliminary tests to always give us a mix up of ideas. It does not point to us directly on what is present. Okay. So that black residue is giving me a mix up. So it may either be copper 2. It may either be copper 2 oxide or nickel 2 oxide or iron 2 oxide depending. Okay.

[00:47:13]But you're not very sure. So what you do you write all of them there. You write all of them there. Okay. So that is how you go about that. We are going to have sample questions on how we are going to be doing this and hopefully I wish I had uh I don't know but I think I need to maybe do this in a lab. I need to do it in a lab one time. One of the sample questions maybe two questions I do it in the lab and you be doing me seeing me doing the experiment. I think maybe it may maybe make a lot of sense.

[00:47:45]But the problem is that when you're when you're doing this and you're using a camera, the quality of the video becomes very low because the video has to move first of all to the satellite and then it comes to you. So it's really a little bit very challenging. That is why I'm trying to handle it theoretically. But even the examples, the practical examples, we can try to handle them theoretically. That is still also okay.

[00:48:10]So I think we are okay up to that point.

[00:48:12]Are we fine up to that point?

[00:48:40]I'm seeing K's hand is up.

[00:48:44]Please unmute.

[00:48:47]K, you can unmute.

[00:48:50]>> Yes. Good afternoon, sir.

[00:48:51]>> Good afternoon.

[00:48:53]>> So, I'm asking about the residue part. If I'm analyzing that part, what do we add to the solid to form that residue?

[00:49:06]>> What do we add to the solid to form that that residue?

[00:49:09]>> The residue all we just heat it as you said?

[00:49:12]>> Yes. You heat when you heat after you heating that residue is going to be formed.

[00:49:18]Okay. So it's the effect of heat.

[00:49:21]You only you only hit the solid when it's without any mixture when added water that solid directly. I said when you heat the solid it is going to decompose to give you an oxide and a gas. So that oxide is going to come up during the heating.

[00:49:42]>> Yeah, that is what is going to happen.

[00:49:46]>> All right. But at our school they told us that you have to first add the residue sorry the solid to water and then you form the residue which you get after filtering.

[00:49:57]>> Now there are different residues that we have. There is a residue which is as a result of heating but then there are those residues which are as a result of filtration.

[00:50:08]>> Okay.

[00:50:08]>> Yes.

[00:50:08]>> We have not yet reached those residues which are as a result of filtration. We are looking at the residue which is as a result of heating. But there are also residues which are as a result of of filtration.

[00:50:21]>> Oh >> okay. We are going to see those residues also.

[00:50:25]>> All right.

[00:50:26]>> Okay.

[00:50:33]Okay. So that is that is basically that.

[00:50:37]Now let's look at the other preimminary test that is C.

[00:50:42]The preliminary test there is going to be on solubility.

[00:50:53]The aspect of solubility. Okay. The preliminary test there is going to be on solubility. Now when when you get these salts usually most of these salts the test that we need to for us to get the cations okay the cations and the onions of these salts we need to dissolve of those salts in either in most especially in water so that those cations or onions can become free to move and then we can easily test for them. Okay. So in our analysis most of the times we are supposed to dissolve those things in water. Okay. And dissolving it in water to form solutions. Okay. Now the examiner can either give you a mixture.

[00:51:40]The examiner can either give you a mixture of soluble salts. So that is the first case. The examiner can give you a mixture of soluble of soluble salts.

[00:51:54]a mixture of soluble salts. And when he gives you a mixture of soluble salts, what does that mean? That means that for them they are going to dissolve in water. For them they will completely dissolve in water.

[00:52:11]They completely dissolve in water to form a solution. Okay? And you should be knowing what a solution is. A solution is a mixture of two or more things that are going to form for us a clear kind of mixture, a clear solution. Okay, so that is the first case that the examiner can do. He can give you soluble salts that are completely soluble in each other.

[00:52:36]Okay, and then they are going to dissolve in water to form for us a a solution. So the color of the solution in this case is going to give us a clue on the cation that is that is present.

[00:52:50]The color of the solution that has been formed is what is going to give us a clue on the cation that is that is present. Firstly you may have a colorless solution.

[00:53:03]A colorless a colorless solution. Okay.

[00:53:07]That colorless solution there is remember we say the non transition the non-transition metal cations for them they are white solids. Usually white solids dissolve in water to form for us colorless colorless solutions. So the moment you dissolve that thing in water and you see a colorless solution, it shows us that in that thing we having non transition metal metal cations. We having a non transition metal metal.

[00:53:39]Okay. Then after if at all I dissolve it and I get a colored solution.

[00:53:46]a coloric a colored solution and that colored solution there is going to be the same okay same as the color the color of the cation okay so there you're going to deduce the cation that shows that color the cation that shows that shows that color that shows that color Let me explain that point. I know it's a little bit compact. So for example, I've dissolved something and I've gotten to get a blue a blue solution. Okay, I've dissolved the salt completely and I've got a blue solution. By now you should be knowing that the cation that gives us that is appears blue is actually the copper 2 ion. Okay. So because you have gotten a blue solution that means that a copper 2 ion can be suspected to be to be present. If I get a green solution, what do I suspect? You should be knowing the cations that give us that appear green.

[00:54:52]If it appears green, it means they can still dissolve to form for us a green a green solution. So you can have the nickel 2 ion, you can have the chromium 3, you can have the iron, the iron 2.

[00:55:05]Okay, like that. Then maybe if I have a a brown solution, a brown solution, what do we have there?

[00:55:14]You can have maybe iron 3 because for it we said it appears brown. Then if I have a pale pink solution, a pale pink, a pale pink solution there, you can easily have the manganese manganese to iron like that. So the color when it forms a colored solution the cation that you're going to suspect is going to be the cation that is due to that due to the color of the solution.

[00:55:45]Okay. So that is that so you can dissolve given salts when they give you a mixture of soluble salts they can dissolve completely in water to form for you a solution and I've said that the color of the solution is what is going to give you a clue on the cation that is that is present. So that is the first case when you're given a mixture of soluble of soluble salts.

[00:56:11]Okay. So I hope that is okay. How do you know that you have been given soluble salts? When you dissolve them in water, it forms for you a clear a clear solution.

[00:56:23]So I hope that part is okay on solubility.

[00:56:29]When you have been given a mixture of soluble of soluble salts.

[00:56:58]Okay. Are we fine up to that point?

[00:57:17]So that color can give us a clue. So if you have been given a mixture of these salts, mixture of soluble salts, when you dissolve them in water, you're going to form a solution. Okay? And the cation that you're going to suspect is going to be due to the color of of the solution.

[00:57:34]Okay. What if sometimes the examiners can give us a mixture? Okay. Two. The examiner can give us a mixture.

[00:57:46]A mixture of a soluble plus an insoluble an insoluble salt.

[00:57:57]they can give you a mixture of a soluble and an insoluble salt. Okay? So when you go ahead and dissolve of that in water, you're not going to form a solution.

[00:58:07]Okay? So that one there is going to partly or it's going to partially dissolve. It's going to partially dissolve in water to form to form. Now it's not going to form a solution but what the word we are going to use to describe that mixture that has been formed the mixture of the solution from the soluble salt and then the undissolved particles from the insoluble salt is going to be what is going to be a suspension that is the word we are going to use a suspension.

[00:58:43]So when you dissolve something in water and you do not see a clear solution being formed that means you are having a mixture of a soluble salt and an insoluble and an insoluble salt. So it means that it has partly dissolved to form a suspension. And usually when you form a suspension the next step in your analysis is going to be followed by filtration.

[00:59:07]Filtration it's going to be followed by by filtration. So with when you filter, you're going to go ahead and obtain two things. The salt that dissolved is going to appear in the filtrate. Okay? The one that dissolved is going to form for us is going to form for us the filtrate.

[00:59:34]Then the one that has not dissolved is now going to form for us the residue which the other guy was talking about.

[00:59:41]The residue is the one that is going to be formed there. Okay. Now what how do we suspect the cations and onions present? We suspect the cations and onions present basing on the color of the filtrate and residue. basing on the color of the filtrate.

[01:00:02]basing on the color of the filtrate and and residue basing on the color of the filtrate and residue. For example, I have dissolved those things and I have gotten a colorless a colorless filtrate. Okay, because I'm having a colorless filtrate, I can go directly to suspect the nontransition metal cations to be to be present. Non transition metal cations, then I can go ahead and also have a white residue.

[01:00:38]Okay, a white residue. So if I have a white residue, I can also go ahead and suspect still a nonransition metal cation to be to be present. So the color of the residue and the filtrate can give us a clue on what is on what is present.

[01:00:55]Okay. Then maybe again you may have you may have u you may have maybe maybe a colorless filtrate.

[01:01:08]You may have a colorless a colorless filtrate. That one still is non transition. Okay? You still suspect the non-transition met. And then you go ahead and have a green you will have a green a green residue. So when you're having a green residue you're going to suspect those cations that have a green color among the transition. You can either have chromium you can either have nickel too. Okay. You can either have ion ion too. Okay. And there are many many more other combinations depending on the experiment you are doing and depending on what the examiner or the setter of the question has given you.

[01:01:50]Okay. So that is what is going to happen when you're having a mixture of a soluble and uninsoluble salt. They partially dissolve to give us a suspension that is going to be followed by filtration. So the cation and the onion that we are going to suspect is going to depend on the color of the filtrate and on the color of of the residue. Okay. So that is that somebody was raising up their hand. Who is that?

[01:02:22]There's somebody who was raising up their hand.

[01:02:31]Okay. safe maybe it was a mistake I hope we have understood up to that point okay solubility it's a very important step whenever you're doing the practicals okay when you when you mix your salts in when you dissolve it in water and you form a clear solution just know the examiner has given you a mixture of soluble salts okay we are going to go ahead and analyze how we are going to treat that in the next lessons okay but for now I'm I just want to give you the general chemistry then how we are going to handle the practical exactly and our presentation of the information I'm also going to handle that so a colorless solution there then uh if at all you're if at all you dissolve and you get a suspension meaning you're going to have a solution that is having some undissolved particles in it that is a suspension so in your mind you should know that that examiner has given me a mixture of a soluble salt and uninsoluble an insoluble salt.

[01:03:37]So, I hope that is fine. If you're okay up to that point, please give me a Y on the chat.

[01:03:53]You okay up to that point? Please go ahead and give me a Y on the on the chat.

[01:04:02]So that we proceed and look at the last part of the preliminary, the preliminary tests.

[01:04:25]Only 13 people have given me wise.

[01:04:32]What is happening to the rest of the people?

[01:05:32]so it means members are okay with that somebody say what if I don't consider solubility how are you going to how are you going to to investigate the effect of an alkali on a a solid directly you cannot Okay, but we are going to see the order of how we are going to be doing our tests. Okay, for now let's be interested so much in the chemistry.

[01:05:59]Okay, we need to be interested so much in in the chemistry.

[01:06:04]That is what I want us to be interested on very much for now. Okay, but the way we are going to be doing the tests, it is going to make a lot of sense. Okay, but let's first understand this chemistry.

[01:06:16]That is what I want us to focus on.

[01:06:20]Then after the other test here that is going to be after solubility we are having color of solution.

[01:06:35]C is solubility then D is going to be the effect of alkanes.

[01:06:46]Let me start with the effect of sodium and sodium hydroxide effect of sodium hydroxide hydroxide solution. So let's look at the effect of these alkalies. Now we are mostly interested in the chemistry. Okay. The way we are going to apply this effect of sodium hydroxide I'm going to show you so that we'll be able to do the test practically in the lab. But for now let's understand the chemistry. Now when you look at the effect of these alkalies that is either sodium hydroxide or ammonium hydroxide. The first thing that you need to know is that all the cations form precipitates.

[01:07:30]All the fat ions form precipitates with sodium with sodium hydroxide. So all the cations we are considering here they form for us precipitates with sodium with sodium hydroxide. But the difference is going to come in in that usually in the lab what happens is that this sodium hydroxide is always going to be added in excess. Okay, it's going to be added in excess. So all the cations form precipitates with sodium hydroxide.

[01:08:07]But the difference is going to be that some of them form precipitates that are soluble in excess sodium hydroxide.

[01:08:16]Some form precipitates that are soluble in excess sodium hydroxide.

[01:08:23]Some of them form precipitates that are soluble in excess sodium sodium hydroxide. Okay. So that is where we are going to be using. This is the one we are going to be using to distinguish most of the most of the cations from the others. All of them form precipitates with sodium hydroxide but some of them form precipitates that are not that are not soluble. Okay. So we are going to go ahead and uh and analyze that. So here I'm going to have sample observations then I'm going to have deduction then I'm going to have a deduction.

[01:09:11]Okay. Now now when you're looking at the thing with sodium hydroxide the issue here is not that there is not going to be precipitate formation. No, the issue here is that in that in that thing there is that precipitate going to dissolve or it's not going to or it's not going to dissolve. So let me start with this assuming I've gotten a white precipitate that is soluble in excess sodium hydroxide.

[01:09:37]White precipitate that is soluble in excess sodium sodium hydroxide. which are those ions that give us white precipitates that are soluble in excess excess sodium hydroxide. They are majorly three and I abbrevate them as what? As zap. Okay, zaps is my abbreviation. I abbrevate them as zaps.

[01:10:00]So that means it is the zinc two ions.

[01:10:03]Okay, the aluminium, the lead two, lead two ion and then the tin to the tin to ion. Those ones form precipitates that are soluble in excess sodium hydroxide. Then another another another you may get a case where you have a white precipitate that is insoluble in excess excess sodium hydroxide. So there are those salts that have precipitates that are insoluble in excess sodium hydroxide. They are majorly three and I abbrevated them as BCM. Okay BCM they are majorly three.

[01:10:39]the barium ion, the calcium ion and then the magnesium magnesium ion.

[01:10:49]So that is that the precipitates that the white precipitates that are soluble in excess sodium hydroxide know them as zaps. For now let's first know them.

[01:10:59]Tomorrow we are going to understand them better. Then the the precipitates that are insoluble here we are going to have BC BCM. Okay, that is basically that.

[01:11:10]Now this two here is for the transition for the non transition.

[01:11:15]These two observations are usually for the none for the non transition.

[01:11:20]Obviously the transition metal ions for them they also form colored precipitates. Okay. But these ones here only form white precipitates. The other ones there for them they form colored colored precipitates. Okay. So for example, So for example here I can have uh I can have maybe a brown precipitate insoluble. Okay, a brown precipitate that is insoluble in sodium hydroxide.

[01:11:52]Okay, which brown precipitate do we have that is insoluble in sodium hydroxide?

[01:11:57]It is iron 3 that we said it's brown. So it precipitate is also going to appear appear brown. So, ion 3 is going to be suspected to be present. Okay. Four.

[01:12:07]What if I have a green precipitate?

[01:12:12]Insoluble.

[01:12:15]A green precipitate that is insoluble in excess sodium hydroxide. The ions we said that are green are they were three.

[01:12:23]Nickel ion 2. Sorry, we said nickel ion 2, ion 3. Sorry, nickel ion 2 and then chromium 3. Okay. Now in this case the ones that are insoluble in sodium hydroxide are going to be are going to be ion 2. It forms for us a green precipitate which is insoluble in sodium hydroxide. Then we are going to have nickel nickel 2. We are not going to have copper 2. Copper 2 does not form for us a green a green precipitate insoluble. Okay. Then we may also have five. We may also have a green precipitate which is soluble.

[01:13:03]A green precipitate that is soluble in excess sodium hydroxide. There is only one transition metal transition metal and cation that forms a precipitate which is soluble in sodium hydroxide and that is the chromium chromium 3. You're going to have chromium 3 there. This one is the one that forms a green precipitate that is that is soluble in excess sodium hydroxide. But that green precipitate dissolves in sodium hydroxide to form for us to form for us a green a green solution that is chromium chromium 3. Okay. Then the other one we have another one here assuming I'm having a blue precipitate insoluble. Okay. a blue precipitate that is insoluble in sodium hydroxide.

[01:13:57]Okay, which one should we suspect to be there? We can suspect copper. Copper 2, it's the one that forms for us blue precipitates. Okay, copper 2 is there.

[01:14:09]Then there are some that I have written here as being unique. There are some that are a little bit unique or for them their behavior is a little bit different from the others. Okay, one of them is that you can have a green PP. Okay, insoluble in excess.

[01:14:32]However, when you leave that precipitate to stand for a while or when you leave it for some time, that precipitate turns to become brown. Okay. So you can have a green precipitate insoluble and turns brown on standing and turns brown on standing turns brown on on standing. That green precipitate there is going to come from ionic ion 2. The reason why it turns brown on standing is due to the area oxidation. Okay? due to the area oxidation oxidation of ion 2 to ion 3.

[01:15:17]So when ion 2 is oxidized to ion 3 that thing is going to appear appear as brown. So this one here is a little bit unique for only ion ion 2. Then also number eight you can have a a white precipitate. Okay.

[01:15:36]Still insoluble.

[01:15:38]Insoluble in excess sodium hydroxide.

[01:15:42]Okay. However, it is going it is going for it. It turns it also turns brown on standing.

[01:15:50]Turns brown on it. On standing. What are we going to get? The major cation that does that is the manganese. The manganese 2 ion. It forms a white precipitate that turns a little bit brown on it. Turns brown on standing.

[01:16:09]That white precipitate turns brown on on standing. Then the last one is going to be for the cobalt. Okay, cobalt 2.

[01:16:16]Cobalt two for it what it does is that it forms for us a blue precipitate.

[01:16:24]But that blue precipitate is also insoluble in excess sodium hydroxide.

[01:16:29]insoluble in excess and it turns brown also on standing for which it turns brown on on standing.

[01:16:39]That one there the iron that we have there is majorly cobalt cobalt to iron.

[01:16:45]It is a blue precipitate that turns brown on turns brown on standing.

[01:16:58]Somebody's uh has raised up their hand.

[01:17:02]Javvis you can unmute.

[01:17:06]Um master uh how does really does have any color that you can see that it is less white and soluble doesn't form any color that it is colorless.

[01:17:22]>> Pardon?

[01:17:23]>> I'm asking how can I verify insoluble and soluble in the appearance to know that this is soluble and this is insoluble.

[01:17:33]>> Okay. Now something which is soluble okay is something that you see the solution is really clear when you look through the test tube that solution there is clear there is no particle that you're going to be seeing inside that solution okay but if something is insoluble you're going to continue seeing some particles inside okay some particles that are still roaming inside the solution and sometimes they are going to actually they actually look a little bit bigger sometimes Especially for those precipitates that one you will know that that precipitate has not has not dissolved. When you look at it practically you will just see that this precipitate has dissolved. Okay. The reason why you're not able to visualize it is maybe because you have not been able to see it very well. Is maybe because you have not been able to see it very well. But when you see it in the lab, something which has dissolved does not have suspended particles in it. But a precipitate that has not dissolved has some particles that are actually suspended in it. The particles that have not yet have not yet dissolved. So that is how we do that.

[01:18:44]So this is the action of sodium hydroxide on all those cations. You need to be able to sit down and memorize this action because it's going to help you in exams. All the cations are going to form precipitates with sodium hydroxide.

[01:18:59]However, some of them are going to form precipitates that are soluble and some of them are going to form precipitates that are not that are not soluble. Okay, the ones that are soluble, I've summarized them here. The white precipitates that are soluble are reser.

[01:19:16]So just scrum that the white precipitates that are insoluble are the BCM, barium, calcium and magnesium. And then the only transition metal cation that forms a solution that a precipitate that is soluble in sodium hydroxide is the chromium is the chromium ion. The rest of them form for us precipitates that are insoluble in sodium in sodium hydroxide. So you need to go ahead and summarize that information and make sure that is part of you and is in your brain. Okay. So as you're doing the practical that information has to be in your head.

[01:19:55]Okay, Harmon's hand is up. Please unmute.

[01:20:00]Okay, maybe it was a mistake.

[01:20:04]So that is that. Okay, on the action of sodium sodium hydroxide. Okay, you unmute harmony.

[01:20:12]>> So now I'm having two questions. The first one is you've mentioned a bit about the precipitate changing color due to oxidation. My first question is why is it that that doesn't happen when you've dissolved it in water? Then my second question comes here that if you've been given a mixture of transition and non-transitional, how do you note that observation?

[01:20:33]>> Pardon pardon pardon pardon. I'm not I'm not getting that. Pardon your first question. My first question is you mentioned that for some for some precipitates they are unique in that when you leave them to stand they change color due to a oxidation. So my first question is why isn't it that that area oxidation doesn't occur when they're dissolved in water. That's my first question. Then the second one is if you've if you've been given a mixture of a salt of a transitional cation and one which is non transition and you've and you've added sodium hydroxide in excess.

[01:21:09]How do you note that observation?

[01:21:12]>> How do I note the observation? I've been given a transition and a non a non transition. Okay. Now what is going to happen there is that let me first start with the first question whereby you have been we are saying that in water there is no oxidation okay why because when you dissolve that salt in water what are you going to have you're going to have the salt existing in form of it is ions to manganese manganese 2 ions so these ions cannot be cannot be oxidized to their respective ions due to air. However, when you dissolve them in sodium hydroxide, what is going to happen is that iron 2 is going to form a precipitate that is called iron 2 hydroxide. Okay, manganese 2 is going to form a precipitate which is manganese 2 manganese 2 hydroxide. These precipitates now for them they can be oxidized by air to their respective to a higher power of their of their oxidation state making them to appear appear brown.

[01:22:21]Okay. So that is that. So that is basically that I hope that has been understood.

[01:22:27]Okay. Then somebody is talking about the mixture. The mixture. Now that one we are going to handle it when we are looking at the examples specific examples. What I'm doing here is just the general chemistry. Okay. When I finish this general chemistry we are going to go ahead and look at the specific examples on how we are going to be handling that.

[01:22:50]Harmon I answered that question.

[01:23:01]Somebody's saying how about salts that are completely completely insoluble.

[01:23:06]Salts that are completely insoluble are going to be dissolved using using u using boreta using a dilute acid. Okay.

[01:23:15]But you're going to have rare cases of salts that are insoluble in water. We are going to have that analysis tomorrow on the exact exact kind of exact things that are going to be taking place in the practice. Okay, that analysis is going to take place tomorrow. So that is the effect of sodium hydroxide there. Okay, so that effect of sodium hydroxide you need to be able to get it. So I hope we have all gotten the effect of that sodium hydroxide.

[01:23:54]Somebody's saying uh Anela is trying to say something. Maybe let me allow you to unmute. I'm not understanding.

[01:24:06]Anela is saying what is Anelka is saying what is Boreta?

[01:24:18]Hey.

[01:24:19]Okay. Now that word now you know I'm I'm actually anot by tribe. Okay. So because I'm an by tribe that means that there are some words that our mouth is accustomed to. For example Mugganda will be will be will be accustomed to saying will be accustomed to saying mu. She said maybe bambi. Okay. Mugganda will be accustomed to saying bambi. That girl came and told me this. Bambi. this and this happened. Now for us its word boreta okay is you know is also that word boreta there's a way somehow it it comes out in our conversation so I don't know maybe I mentioned it here by accident okay so that is that on sodium hydroxide then the last one that I'm going to look at is going to be the action of of ammonia hydroxide the action of ammonium ammonium hydroxide.

[01:25:29]All right. Now, when it comes to ammonium hydroxide, most of the things are going to remain the same as the ones of sodium hydroxide. Okay. However, there are a few cations. the cations that are soluble in ammonia hydroxide are not are not the same as the ones that are soluble in sodium in sodium hydroxide. So for example, I'm going to have here an observation and then I'm going to have here a deduction deduction. Okay. So one of the cations that are soluble in excess ammonia they are only basically three. There is the zinc 2 ion. Okay. There is the nickel 2.

[01:26:15]Then there is there is uh there is the copper copper 2. Those are the only cations that are soluble in sodium hydroxide. So for the zinc 2 it gives us a white precipitate soluble white precipitate soluble soluble in excess in excess ammonia.

[01:26:37]Okay. to form obviously a colorless solution and that one is only one the zinc to the zinc to iron. Okay. Then for nic it is precipitate beside this green.

[01:26:48]Okay. So for it it gives us a green precipitate soluble in excess ammonia to form. Okay for it it forms not a green solution but it forms a pale blue solution.

[01:27:04]So make sure you take note of that. For nickel 2, the thing dissolves to form a pale blue a pale blue solution. So there we have the nickel two the nickel 2 ion right. Then for for copper 2 for copper 2 what are we going to have?

[01:27:21]We are going to have a deep we are going to have a blue precipitate. Obviously copper 2 forms a blue precipitate.

[01:27:30]So you're going to have a blue precipitate soluble in excess sodium in excess ammonia hydroxide to form to form for us what?

[01:27:43]It does not form for us a blue solution but it forms for us a deep blue solution.

[01:27:50]A deep blue a deep blue solution. That one there is only for copper or copper 2. So these are the unique ones when it comes to ammonia. The rest are going to remain are going to remain the same.

[01:28:04]Okay. The rest are going to remain the same as as for sodium hydroxide. Then the other unique one that I have here other unique one I'm having here is for the calishium the calicium ions is when you treat let me write let me write let me just write classify this here.

[01:28:27]Let me write this one here. I'm having a white precipitate insoluble.

[01:28:34]When I have a white precipitate insoluble, which cations am I going to have?

[01:28:40]White precipitate insoluble. The cations I'm going to have there is going to be the aluminium ion lead to two ions, the barium ion, the magnesium ion, the tin to the tin ions. All those precipitates are insoluble in ammonium ammonium hydroxide. However, there is always one that gives you no observable change.

[01:29:10]no observable observable change for which it does not form a precipitate with ammonia. There is only one cation that does that and it's the calcium the calcium ion for which it cannot be in position to form a precipitate with with ammonium ammonium hydroxide and that observation can be explained using the relationship between solubility product that is Ksp okay and then ionic ionic product I taugh that in the third term holiday okay the relationship between solubility product and ionic product can explain why we have no observable change with withium calcium ion. The reason is because the the the the concentration of the hydroxide ions that have been given the concentration of the hydroxide ions that have been provided by the ammonia okay is very low for the ionic product of kalishium hydroxide to exceed it solubility it is solubility product.

[01:30:18]However the rest are going to remain are going to remain the same. So those are the unique areas that we are having when it comes to ammonia monium hydroxide.

[01:30:28]The cations that form precipitates with ammonium hydroxide are only three. The zinc 2, nickel 2 and then copper, copper 2. The rest are going to remain the same as in sodium in sodium hydroxide.

[01:30:52]So I hope members are okay with that.

[01:30:59]So those are the preliminary tests that we are going to be having in our analysis of of the kions. Okay.

[01:31:12]People here are surprised about my tribe. You people have been paying money to my number and you even read my name but you cannot tell that this name is a little bit familiar.

[01:31:41]Okay members are we okay up to this point? Can I say that I have made a statement in some of the theory as it comes to inorganic analysis.

[01:31:53]Okay.

[01:31:55]So those are the preliminary tests that we have. Okay. Then obviously our time is far much spent and I see most people are leaving the lesson. Okay. The time has gone. So that means that in the next lesson of tomorrow, I think tomorrow we having practical. Let me check the time table.

[01:32:15]We are going to do this practical work very well. By the time we are done, you should be very good in your understanding of the practical the practical work. If you're fine with that up to now, please give me a while in the chat and then we'll be able to close.

[01:32:35]If you're not okay, give me an X.

[01:32:46]All right. So I think for that I think we should be able to stop here for today. Okay. Let's stop here for today.

[01:32:53]We go and have a rest. In the evening we are not going to have a lesson. It is in the time table that is free time. Okay.

[01:33:00]Use that time and do something on the Google drive and then tomorrow again we meet. In the morning we have biology practical. In the afternoon we are having uh chemistry practical. Then in the evening we are having something else. I forgotten the time table but that is what we have. So let's rest for now and then we meet tomorrow in the morning after lunch then also in the night. So tomorrow is going to be more packed. Right? So let's stop here for today. Let me see you people tomorrow.

[01:33:28]Right? So have a have a nice season.

[01:33:32]have a nice uh a nice day.

[01:33:39]Somebody's asking me about those people that what about people who are in who are in this section. I usually don't handle this scholars. Why? Because I'm also busy during during school time.

[01:33:51]Okay. I'm also busy. I also have to study. I also have to read. Even right now, I'm I actually have to balance both sides. But we shall be fine. All right.

[01:34:00]Have a nice time. See you see you tomorrow.