11th Class Chemistry Chapter 16 | Tests for Identification of Anions (16.6) | 11th New Book 2025

[00:00:07]Assalamu Alaikum Student I am your Chemistry teacher Mohammad Abdullah Zia.

[00:00:12]Today we have to study topic 16.6 of chapter number 16.

[00:00:16]In which we have to identify the anions and how the anions are identified.

[00:00:23]Look, we have two things.

[00:00:25]First of all, we need to know this is like NaCl, okay? In this, Na is positive and what is Cl? Negative. Now what do we have with this one? is a cation. And what is this one? We have an anion. So both anions and cations are radicals. There are salts.

[00:00:43]We identify these salts. The first method is to identify them with dilute sulfuric acid and then with concentrated sulfuric acid. If they react with them or with the solution of barium chloride, then we identify that the salts we have are definitely radicals.

[00:01:04]We use the word radicals for salt. And then it says identify the carbonates.

[00:01:09]How to identify carbonates?

[00:01:11]What do you mean? Look, I have a box here. Box number A. Here the box number is B and here the box number is C. Now here is a different carbonate.

[00:01:22]I don't know which one or whether it's sodium carbonate, magnesium carbonate or any of the aluminum carbonates, etc. I have to identify whether this is really carbonate or not.

[00:01:33][nasal sound] There are three steps to that. Step number one involves experimentation. The second involves observation and the third involves inferences. If we do these three things then our identification is done.

[00:01:44]What's the first thing he says?

[00:01:46]In the experiment, you have to take a test tube and put the powder taken from here in that test tube.

[00:01:50]Take 2 grams of solid carbonate in a clean test tube. Look, we have added the powder. After that add 500 5 cm.

[00:01:58]Cube dilute HCL. Then we have to add HCL into it.

[00:02:03]As soon as HCL is added, a gas will evolve from here.

[00:02:06]You have to take that gas to the other side through lime water with the help of a capillary tube.

[00:02:11]Now what will happen to the lime water as soon as the gas coming out passes out? Milky. So what happened to us was that we took 2 grams of solid sodium carbonate in this test tube and added dilute ICl to it, and gas came out of it. We passed that gas through lime water. What happened to lime water? Got it. So we said that this carbonate identify means this is carbonate.

[00:02:36]Carbonate is like CO3, when it is put in hydrogen, water and CO2 are formed. If carbon dioxide is added to carbonate i.e. CaOH twice, then calcium carbonate is formed which is white. It is milky. This lets us know.

[00:02:49]That is one test is complete. If we have what he says are four boxes.

[00:02:55]One contains chlorine, one contains Borromean and one contains iodine. But I don't know which chlorine is it? Which one is Borromean?

[00:03:01]Iodine in all three boxes, that is, I have ordered three boxes from the market. I asked him to send me chlorine, Borromean and iodine.

[00:03:08]So they sent me.

[00:03:10]But I am not able to find out this because there is nothing written on it. So I want to see that now. Which box contains which chlorine, which Boromi. So what's the first thing we'll do for him?

[00:03:20]Experiment. We will take a test tube and put 2 grams of sample from the first box inside that test tube. Ok?

[00:03:27]Then what will we do? We will add 500 cm cube distilled water in it and then we will add a few drops of nitric acid in it and finally we will add AgNO3 which we call silver nitrate.

[00:03:39]How many things have you put in? Four. In the first one we have put that sample of that powder. Then we added distilled water from it. Then nitric acid was added and finally silver nitrate. If you have taken powder from this box and the color of that powder becomes white precipitate.

[00:03:54]Ok? In the presence of these ammonia, it means that it is chlorine. What these infusions have is that it is chlorine. And if we take a box which is creamy yellow in color, then understand that it is bromine. And if it is made of bright yellow color then what is that? We have iodine. After that comes the identification of the nitrate. We have how to identify nitrate.

[00:04:14]We have some boxes lying around and we have to tell them about nitrate. First of all we have to take 2 grams of solid sample in a test tube. In that we have to take 2 grams of any solid sample which we want to check whether it is really nitrate. What do we have to do inside it? To dissolve, add 500 ml distilled water and put NaOH in it and also add aluminum powder. I have added four things. First of all he has put the sample.

[00:04:39]Then you added water to it and then added aluminum powder with NaOH. So ammonia gas will come out from there and we have to place litmus paper on the mouth of the test tube. As soon as you place the litmus paper, it will turn from red to blue. Which revealed that this was its observation. So it was found out that it was nitrate. The powder we see is nitrate. If this happens then we will say yes, it is definitely confirmed that it is nitrate. Otherwise it is not. We have identification of the ion which says identification of sulfate. We have to look for sulphate and we have a box lying around. Is it sulphate or not? For that, first of all we will experiment. Then after that we will do observation and lastly we will do inference.

[00:05:21]Well, what that experiment is, you have to take a test tube.

[00:05:25]What you have to do is take some powder from this box and put it inside that test tube. 3 grams of solid sample has to be added to the test tube which is a clean test tube. You have to stir some water in it. It will be added.

[00:05:38]Add a few drops of nitric acid and add barium nitrate at the end. How many things to put in? Four. First you have to put the sample which you want to check whether it is sulphate or not. Then you have to add water and then after that you have to add a few drops of nitric acid and at the end you have to add barium nitrate. As soon as you add it, heavy white coloured precipitates are formed in it which indicate that SO42 is negative indicated. So this is the reaction in front of it.

[00:06:04]Simple barium sulphate is formed with us.

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