ACIDS, BASES AND SALTS REVISION || ECZ 2020 SCIENCE P2 || WELL EXPLAINED

[00:00:00]Hello viewers. Welcome back to to my channel. So now, let's look at this question. So this is acids, bases, and salts. This came I mean this question came in uh 2020. Yeah, so this is 2020. So the question is saying Actually, make sure that you subscribe.

[00:00:17]Yeah, ensure that you do what? You subscribe.

[00:00:21]And also you leave a like. Okay, so the question is saying so we will just summarize it.

[00:00:27]Study the flow diagram below and answer the questions that follow. Okay? We have solid P which is heated to produce gas Q which turns damp red litmus paper blue and gas R.

[00:00:42]Before we go any further, when you see a gas turning red litmus paper blue, just know that it is ammonia.

[00:00:50]You should always know that.

[00:00:52]A gas Actually, when anything turns red litmus paper blue, that is alkali, right? Yeah, because acids they turn blue to red. Then alkalis or bases turn red to what? To blue. So this is an alkali, but specifically, if it is a gas, then it means it is ammonia.

[00:01:11]So we have ammonia. So we are producing ammonia from this solid. Then it dissolves in water to form solution T which reacts with sodium hydroxide to form solution U, water, and again this same gas turning red litmus paper blue.

[00:01:26]So this is ammonia again. Then when solution T reacts with silver nitrate, it forms solution W and white precipitate. So this solid this solid P is no other than ammonium chloride. And I'll explain why. So this is ammonium chloride.

[00:01:46]Ammonium chloride.

[00:01:52]So this is written as uh ammonium chloride. This is our P.

[00:01:59]So, NH4Cl.

[00:02:02]This is our P. Why? When this decomposes when you heat it, it produces ammonia, NH3 plus hydrogen chloride. So, these are the two gases here. So, the gas which is which is turning red litmus paper blue is what? Is ammonia. The other gas R is hydrogen chloride. So, this is R, this is our Q. This is P.

[00:02:27]Then, we come here.

[00:02:29]So, it is dissolved in water to form solution T. That's what they are telling us here.

[00:02:34]What is solution T? So, when it is dissolved in water, it will still be ammonium chloride. Nothing will change, but it will only become a solution.

[00:02:44]So, ammonium chloride solution, which is solution what? Solution T, according to the question.

[00:02:51]Solution T. When this solution T reacts with sodium hydroxide So, solution T reacts with sodium hydroxide. This is sodium hydroxide. It forms what? U water and the gas, which is ammonia. So, what is U? So, U is sodium chloride.

[00:03:10]Okay? So, this sodium will get this chlorine here to form sodium chloride plus they are telling us that we have water and the same gas, this one, which is uh ammonia, NH3.

[00:03:26]So, this is water, H2O.

[00:03:29]So, this is what is happening here.

[00:03:32]So, this is our U and this is our Q.

[00:03:38]Here, plus our Q. Yeah.

[00:03:41]Then, this same now reacts with silver nitrate to form solution W.

[00:03:47]Okay?

[00:03:48]So it reacts with this now reacts with um So, we can say here it reacts with silver nitrate. This silver nitrate.

[00:04:06]No, no, no. Silver nitrate. Yeah, like this.

[00:04:10]So, when it reacts with silver nitrate, they are they are telling us that it produces solution W.

[00:04:17]So, what is solution W?

[00:04:20]So, W is ammonium nitrate solution because this is ammonia. Then this is nitrate. So, we will have ammonium nitrate what? Solution. So, here we will we will have ammonium nitrate solution.

[00:04:40]Which is solution what? In the question they are telling us that this is solution W. So, solution W is what?

[00:04:46]Ammonium nitrate solution.

[00:04:48]Then again, they are telling us ammonium nitrate solution plus X.

[00:04:54]So, two things are being what? Are being produced. We have X also. So, what is X?

[00:05:00]So, X is what? X is silver chloride. So, we say this plus a a precipitate.

[00:05:11]So, this is silver chloride. Because silver chloride is solid. And when you see a precipitate, just know that it is solid. So, this is a solid one. So, this is silver chloride because this silver is going to get the chlorine from this solution and form silver chloride.

[00:05:32]Okay? So, this is it. So, let's now break down the questions. So, the question are saying identify P, Q, W.

[00:05:39]So, from here now we can say P.

[00:05:45]Okay, so, let me write here. So that you see.

[00:05:50]Yeah, so P, our P our P Our P is going to be what? We said our P is ammonium chloride.

[00:06:09]Then they want us Q and W. Q and W. So Q is what?

[00:06:17]We said Q is ammonia.

[00:06:23]Q is what? It's ammonia.

[00:06:26]So this is NH3.

[00:06:29]This is NH4Cl.

[00:06:33]Then, what is W?

[00:06:35]So W This is W, the solution I was talking about to say it is ammonium nitrate solution.

[00:06:45]Ammonium nitrate solution.

[00:06:53]Okay? So that is it. So ammonium nitrate solution is NH4 NO3. This is it.

[00:07:04]Then Yeah, it was not visible. Yeah, so this is it. So this is P, ammonium chloride, ammonium chloride. This is P.

[00:07:14]Then Q is ammonia.

[00:07:17]Then W is what? Ammonium nitrate solution. Yeah.

[00:07:22]So this is it.

[00:07:23]Then we have the last two questions. Write the balanced chemical equation for the decomposition of P. I already wrote it there. So P which is ammonium chloride decomposes to form what?

[00:07:41]Ammonia plus hydrogen.

[00:07:44]chloride. This is a gas. This is a gas.

[00:07:48]What about this? So, like they said in the question, they said solid P. So, this is solid.

[00:07:55]So, this is what This is it all. Okay?

[00:07:58]It is balanced already. Then Write the balanced chemical equation for the reaction between solutions T and the aqueous sodium hydroxide. So, this one here. Solution T and the aqueous what?

[00:08:14]Sodium hydroxide.

[00:08:17]When this T reacts with this. So, for T, what did we say about T? Well, we said T is what? T is ammonium chloride. So, the T is ammonium chloride solution. So, this will be ammonium chloride solution reacting with what?

[00:08:39]So, it is reacting with They are telling us when it reacts with sodium hydroxide. So, this is sodium hydroxide.

[00:08:48]Then forming what?

[00:08:50]Well, we we've been given all these substances. And what did we say about these substances? We started with U to say U is what? It's sodium chloride. So, it is forming sodium chloride plus water H2O plus ammonia.

[00:09:13]NH3.

[00:09:15]So, this is the what This is the the equation.

[00:09:18]And this equation is also balanced. You just have to include state state symbols. So, this is aqueous because it is a solution now. It is dissolved in water. Then this is also aqueous.

[00:09:29]Then sodium chloride is also aqueous because this one is also uh soluble in water. Then this is what?

[00:09:38]This is liquid. Then this is what? This is liquid. Then this is a gas. So this is it for this question. Hopefully you've understood.