 Yes, are you there? Hello. Can you hear me? Yes. Okay. So let's solve some questions on this. We have done a bit here. Okay. Try all these questions. 26, 27, 28, 29, 30. One liner. Quickly you tell me. Okay. So done all of you. Okay. For this reaction you can see delta NG or delta N equals to zero. Hence Kp is equals to Kc. For this reaction four plus one five five minus two delta N is greater than zero. That is three. But if I write down the value here, delta N is three greater than one. So Kp is greater than Kc. For this one again, delta N equals to two minus five. That is minus three. Less than zero. Kp less than Kc. Kp, Kc, gases, reactions are related to each other by the expression Kp is equals to Kc, RT to the power delta NG. NG option B is correct. Kp for the reaction, this was found to be this. What is Kc? How do you do the 30th one? So question number 30, Kp is equals to Kc, RT to the power delta N. You convert kilo Pascal into ATM. So one Pascal equals to what? What is the relation of Pascal and ATM? Tell me one Pascal equals to R. If you take 8.314, it will be joule, right? But pressure, since pressure expression we have, so you must have ATM, that's how one second, if you have Kp is given in this, right? So one ATM is equals to, we can approximately take 10 to the power minus five Pascal, 10 to the power five Pascal, correct? So we convert this into, how once again? We can convert this into, you can convert this into ATM and then you can calculate. Excuse me, sir. The screen is stuck, the screen is stuck for us yesterday, the 30th question. It's like one PA is equal to, it's stuck there. Now it's working. So one Pascal is equals to what we can write, 1.01 into 10 to the power five, sorry, one ATM is equals to, we can write. We have Kp is equals to 11.45 kilo Pascal. So in ATM, it would be 11.45 into 10 to the power three Pascal, right? Kilo Pascal is this. Now one Pascal is one by this, so this much would be 11.45 into 10 to the power three divided by 1.01 into 10 to the power five ATM, isn't it? Could you tell me this value? Give me the value over here. Okay, one second. Yeah, Namta, we'll do both way. This is again, we'll do both way. So this approximately we are getting 0.114 ATM, roughly suppose. So this we can substitute here and then Kp is 0.114 is equals to Kc is equals to 0.0821. Temperature is 298. Delta N value is what? Delta N value is 1. So Kc can find out from this. Okay, one more thing you can do. I did not see this. Kp you need to find out. So this value you can also take in Si, right? With this conversion also you can do if you want, you can do this. And then you can also take case P as in Pascal only. You can convert this into Pascal 10 to the power three, you can multiply and that would be equals to 8.314 directly R value you can take. Okay, since kilo Pascal is given over here, if you have the pressure of Kp is given atmospheric, then you can take R value is 0.0821. So I think you will get from this expression also in which Kp you can take 11.45 kilo Pascal kilo Pascal R value is 8.314. What is the unit here? Joule per mole Kelvin into and temperature is what? 298. This also you can substitute you will get Kc. What is the value you are getting? Just check once Kc. Yes, yes, Kc value you will get decimeter cube. Decimeter cube you will get. Tell me the unit mole per liter only or you can also write on decimeter cube, mole per decimeter cube. So 4.62 into 10 to the power minus three. This is what the answer will be. So both way you can do whatever it is comfortable you can do that. Okay, option C is not option B is correct. Option B is correct minus 3 anything. This question you see? Okay, 7 and 9, 8 you let it be, 8 we haven't done yet, 8 you let it be, 7 and 9. What happened? Did you get the answer? Okay, C and B you are getting. See the first one is very simple. This is the reaction given and for this the equilibrium constant is Kp. You need to find out the equilibrium constant of this reaction. Correct. So one thing you see here you can also understand this as a property. Suppose let's say we'll have a equation A gives B. Okay, Kc would be concentration of B by concentration of A. Suppose if you multiply this reaction by any number 2 then Kc dash would be what? It is B by A whole square which is nothing but the previous equilibrium constant by square which concludes what? When you multiply a reaction by a number the new equilibrium constant will be the bar of the old one. New equilibrium constant will be equals to the old one to the bar the number with which we have multiplied the reaction. Right, so Kc this reaction multiplied by 2. So for this one the new the equilibrium constant would be Kc to the bar 2 which is this. So you see this question here we have this N2O5. So first of all we'll revert it. So once you revert it the reaction equilibrium constant would be 1 by Kp because for this one it is Kp, for the Ulta it is 1 by Kp and after reverting it we are multiplying it by 2, 2, 4 and 1 we have here. So this one would be 1 by Kp square option C. Any confusion in this? This you can also take it as the property. If you multiply by a number the new one will have the power of that. Okay, how many of you have done ninth one? Still trying? Should I wait for a while? Okay, I'll do it now. See first of all we'll write down the reaction this kind of you know concepts we haven't seen now but we'll do that. So it is the reaction is 4 HNO3 and all our gaseous species. So we can consider the pressure of all N02 gas plus H2O gas and O2 gas. So initially what happens we have only HNO3 present okay it is not mention over here but we have to assume it like this. Okay like only HNO3 is present over here. Since all our gases so we have certain pressure of O2. Let's see here. So this is the total pressure given. I am assuming P1 is the initial pressure of this HNO3. This is what I am assuming. Okay listen carefully. P1 is the total pressure I am assuming at time T is equals to 0. This kind of concept we haven't discussed we haven't talked this kind of calculation so you can understand. P1 I am assuming HNO3 is present and there is no N02, H2O and O2 present here initially when the reaction is about to start. Generally what happens we do not consider any product present initially. If it is mentioned only then we can consider. If it is not mentioned it means there is no product present when the reaction was about to start. So this means here we have only HNO3 present initially which on reaction on dissociation gives these molecules. Clear? Now when the reaction starts obviously this HNO3 starts dissociating and converting into this gaseous molecule. So I am assuming out of P1 pressure, out of P1 pressure some pressure some part of it dissociates obviously the pressure of HNO3 will decrease and that is 4T we have. Why 4? Because we have 4 over here so when you take 4P the calculation will be easy. You can take P1 minus P also. I will do this one only first but we will solve by this easier to solve why I will tell you. So I said P1 was initially present and out of P1 P dissociates and converts into this. Is it clear now? Tell me. Out of P1 P dissociates and forms this molecules correct. Now you see what is the pressure of NO2 will get over here? What is the pressure of NO2 will get over here? It depends upon the esterotubation. So if 4 moles of HNO3 gives 4 moles of NO2 so 1 gives 1 and P gives P. So we have P pressure of NO2 will get over here. 4 gives 2 so 1 gives half, P gives P by 2. Clear? 4 gives 1, 1 gives 1 by 4, P gives P by 4. Did you get it? How do we get P, P by 2, P by 4? Did you understand it? Because this is the only important otherwise it's very simple. Once you know the pressure you can write down the expression of KPC. I will discuss about this 4P. Just ignore for a minute. Did you understand this? This one I am coming back to this. So what I am trying to tell you, whatever you want, you can assume here. You can assume 4P, you can assume P. If you assume P, then you will get this kind of expression. Now what happens if you take 4P, that is the why 4? Because 4 is the stoichiometric expression. So 4 into this, the advantage of this is what you see. 4 gives 4 mole of NO2. So if you take 4P, then you will get P is the pressure of NO2. Similarly you calculate for H2O. 4 gives 2, 1 gives half. So 4 gives P gives 2P, 4 gives 1, 1 gives 1 by 4. So 4P gives 1 by 4 into P, that is 4P. Oh sorry, P is not 4P. Tell me. No, NO2 is not 4P. See, it's unitary method. I'll tell you. I'll tell you. What I have done, I'll tell you. What is the advantage of 4P here we have that you see? I can say that 4 mole of or 4 mole or pressure you can say, 4 moles of HNO3 gives 4 mole of NO2. So 1 gives what? 1 of NO2. So if you take 4P because 4P is dissociating. So 4P of HNO3 gives what? 4P of NO2. Is this fine? Tell me. Yes, tell me guys. No, we are equating pressure with the stoichiometric coefficient number of moles. Pressure and number of moles you can equate. No. One second, I'll tell you. One by one, you'll go. Did you understand all of you this you understood? Basically, you need to understand 4P amount of HNO3 gives what amount of NO2, what amount of H2O, what amount of O2. Did you understand this? Tell me. Yes or no? Okay. If you see for H2O, so if you have 4 mole of HNO3, then 2 mole of H2O we are getting. One second, Sanshrath, this will see this will come back to that point. If you understand this one also, you'll understand this. It's same only. We can say 4 mole of HNO3 gives 2 mole of H2O. So 1 gives what? Half. But how many are reacting? I am assuming 4P is reacting. So 4P gives what? Half into 4P. That is 2P. Did you understand? So pressure of H2O is 2P. Once again, Sanshrath, once again. If you talk about O2, then we can say 4 of HNO3, just a second, 4 HNO3 gives 1 of O2. So 1 gives 1 by 4 to 4P gives how much? 1 by 4 into 4P, that is P. No, it will be in the same proportion. See, P is different only. For this, this is 2P. For this, this is P. Proportion it is. Value of pressure will be different for different gases. Obviously, with number of moles, the pressure will change. But it will be in the same proportion. I'll come to that on NO2 also. Did you understand for H2O and O2? All of you tell me first. Okay. Now, NO2, what happens? You see? Actually, I have written 4P. Here, I have written by mistake. It should be 4P only. So point is, now this thing, listen to me carefully. Whatever you want, you can assume here. You can assume that 4P is reacting. You can assume that P is reacting. But the pressure of the respective products will change in the same proportion. Whether you take this data or you take this data, your answer will be same and correct. Okay. The advantage of taking this stoichiometric coefficient into P is what? You won't get this kind of fraction. You see? 4 to here 4, this 4, here 4, this 2, then 2, 1 and then 1. So advantage of this is what? That you need to just write down the pressure that you are assuming with their respective stoichiometric coefficient. Like for example, I have taken 4P here. So it should be 4P only. It should be 2P. Is this clear? You understood this? That is what you need to do. Okay. But remember here one thing that this P1, I am assuming it is not given in the question. Yes. For each of this, the pressure will be in the same proportion of their moles because PVs goes to NRT. So pressure and moles are proportional. So with their mole ratio, we can take this. Have you forgot Dalton's law of partial pressure? More number of moles, more will be the partial pressure. Yes or no? I will tell. We will discuss this. This is a new type of questions. We will discuss this when to do, how to do. First focus on this. Try to understand this first. Okay. Wait. So we got the pressure of NO2, this and this. Why we need pressure? Because we need to find out Kp. Kp is what for this reaction, it will be the pressure of NO2 to the power 4 into the pressure of H2O to the power 2 into the pressure of O2 power 1 divided by the pressure of HNO3 to the power what? Clear? To find out Kp, you need pressure of each gases and hence we did this. Correct? But now one more thing here. Like I said, this P1 is not given in the question. So we need to replace this. How do we replace this? It is given in the question that the total pressure is P. You see, if P is the total pressure at equilibrium. So at equilibrium, at equilibrium, total pressure P is equals to what? The pressure of HNO3, the pressure of HNO3 plus the all gaseous species pressure of NO2, pressure of H2O plus pressure of O2. If any solid or liquid is there, you can ignore that simply. Pressure of HNO3 is what? P1 minus 4P. Pressure of NO2 is 4P. Pressure of H2O is 2P. Pressure of PO2 is P. When you solve this, this 4P and 4P gets cancelled. So P1 plus 3P you got. Remember this pressure is the pressure that reacts. And this is the pressure given. So I just write down some other name here so that you won't get confused. Nothing just you see. In the question, what is given you see? Started with pure HNO3. P is the total pressure at equilibrium. Pressure of O2 is given PO2. Okay. So I'm just going to the next slide because I don't have a space over here. One change you do just to differentiate this pressure and this pressure here. I what I'm doing here, I'm assuming this as P2 P2 P2 P2. So here also we have everywhere we have P2 and this is also P2. So what we have here you see the pressure of O2 is P2. So it is given in the question that the pressure of O2 is PO2 only P2 is equals to PO2 and total pressure P at equilibrium is equals to what we have total pressure P at equilibrium. It is this. Let me just go back and check total pressure P at equilibrium is P1 plus 3P2. That is this one P1 plus P1 plus 3P2 given. This P1 is unknown. P1 we do not know. We have assumed it right. P1 we have assumed it right. And and here you see this P is given and P2 is PO2 that is also given here. So what I'll do here I'll find out this P1 in terms of P and P2 because P2 is given in that question is PO2. So P1 is P minus 3PO2. How many of you understood this? It's clear because P1 is not given. P1 we need to find out in terms of total pressure in the pressure of O2 which is given. Now you tell me one thing just we need to do one thing. What is the pressure of HNO3 at equilibrium? The pressure of HNO3 at equilibrium is I just need to go back is P1 minus 4P2. You see here pressure of HNO3 is P1 minus 4P2. P1 we have calculated now is P minus 3PO2 is P1 and P2 is nothing but PO2. So 4PO2. So this would be P minus 7PO2 once again. Once again stress just you understand this. We have P1 in terms of P and PO2. We are trying to find out the pressure of each gaseous component in terms of P and PO2. See you have this question you have this question. In this question only two things is given. One is the pressure of O2 is PO2 and total pressure is P. Hence for all these gaseous species we need to find out pressure in terms of P and PO2. Is that clear? So what I have done the total pressure is given at equilibrium. So we add all these pressure that equals to the given pressure P and when we solve this we get P is equals to P1 plus P2, 3PO2. This 3PO2, P2 is nothing but PO2. You know this pressure of gas O2 is PO2. So P2 is nothing but PO2. That's what I've written over here you see. P2 is PO2 given in the question option you see. P is equals to P1 plus 3P2 total pressure at equilibrium. Now we calculate this P1 in terms of Pn P2 that is this. P HNO3 is this. What is the pressure of PNO2? You see the PNO2 the pressure let's change the color and write down just to avoid any confusion. Okay wait this one I'll choose. P2 is PO2. So pressure of NO2 is 4PO2. Pressure of H2O is 2PO2. Pressure of O2 is PO2 already. So we know the pressure of NO2. We know the pressure of H2O. The pressure of NO2 is 4PO2. The pressure of H2O is 2PO2. The pressure of PO2 is PO2 only and pressure of HNO3 is what? Just now we calculated here. The pressure of HNO3 is this P minus 7PO2. Just all these values substitute will get the expression of KP. So KP expression would be would be I'll write down here. Okay I have to again come back this side. So I'll write down here. The pressure of KP expression would be pressure of NO2 power 4. So 4PO2 power 4 into pressure of H2O power 2. 2PO2. 2PO2 power 2. Pressure of PO2 so only PO2 divided by pressure of HNO3. What we have calculated pressure of HNO3? It will be this side. Pressure of HNO3 is P minus 7PO2. P minus 7PO2 remember that P minus 7PO2. So here it is P minus 7PO2 to the power 4. You see in the denominator we are having this P minus 7PO2. 7PO2 to 7PO2. Just you need to find out this constant. So 4 into 4 is 16. 16 into 4 is what? 16 to 4 is? 64. Right? Anything well 4PO2 power 4. That's what I was thinking. Why I'm not getting any option. Yeah, correct, correct, correct. This is power 4 here. This is power 4. So 4 to the power 4 is what? 256. 256 into 4. 256 into 4. I think 1000 something we are getting. Is there any option with 1000 something? Yeah, 1024. So I think here it will be 1024 PO2 to the power 7 divided by P minus 7PO2 to the power 4. How many of you understood this? It is not that difficult since you're doing it first times maybe you're, you know, getting it a bit lengthy, but it's simple only. Obviously reactant convert into product always. So reactant decreases. See the purpose is initial pressure is not given. I assume initial pressure and then some amount of it convert into this. Obviously the pressure will decrease. I am assuming 4P reason I told you always take like this only whatever the stoichiometric coefficient into the pressure. If it is concentration then 4 into C concentration also you can assume. You'll get this, but since we have assumed this P1 and P2, so you need to find out this P1 or P2 in terms of the given pressure and for that two data is given that the pressure of O2 is PO2, which means this P2 is nothing but PO2. If this is PO2, this is 2PO2, this is 4PO2, this is again 4PO2. So this P1 you can find out once you add this up and equate to the total pressure at the temperature speed and then we substitute in this expression. Yes understood. We have for this. Tell me question number 15. 14 also you can try. 13 sorry not 14, 13 you can try. 13 and 15. 13th one what is the answer? Okay so for the 13th one the answer is D. Why D? Because it says constant temperature and we know Kp or Kc depends only upon temperature. When temperature is not changing Kp remains constant, only one option we have. 15th tell me 15th. 15th one is C. I will do that later. I did not ask you to try question number 14 mother. So there's some reason for that. So we'll discuss that later and then you can try that question. I'll give you that. Okay okay. The question number 15 you see obviously we have two NH3C, two NH3 on the reactant side. If this two NH3 on the reactant side we have so in this give actually we know what happens from this given reaction, this three reaction you need to obtain this reaction by addition or subtraction. Do whatever you want, multiply by some number, add or subtract any of these reactions. The objective is to find out this reaction and to get this reaction whatever operations we have done in these reactions accordingly K value you need to you know multiply divide whatever. That is what the whole thing is but every time you don't have to do all these operations here by looking at the options you can understand what could be the possible answer. Like you see first of all this NH3 in the final reaction we have on the reactant side. Here NH3 we have on the product side. So obviously if you want to take it on the reactant side this reaction you need to revert so this K1 must be in the numerator sorry denominator yes or no K1 must be in the denominator What? To get this NH3 on the this side reactant side and in the given reaction we have NH3 on the product side so we must need to revert this reaction right. So once you revert this reaction then this K1 becomes 1 by K1. It means K1 must be on the in the denominator and for that we have only one option. This kind of trick you can apply like any question. Only one thing you need to keep in mind that none of these should not be there. If it is none of these then you have to cross check it is happening or not. Best way to solve this kind of question is you go through the options only always. Suppose you got one thing that K1 is on the in the denominator then you see what happens if you you know do this K3 to the power 3. So when you multiply with this 3 here then what happens you see are you getting 3h2o here we are getting 3h2o we have 3h2o this side also. So you will have the idea once you go via options. Yes did you get my point understood no yeah easy questions only you will get in this okay you can do it. Okay now on a one small concept we need to understand here to predict the extent of reaction heading right down predicting the extent of reaction. Okay so it's a factual thing here that you need to keep in mind. Suppose we have a reaction A plus B gives C plus B so KC would be concentration of C concentration of B by concentration of A into concentration of B. What we have observed you know it's a factual thing experimentally what we have observed if the value of KC is greater than 10 to the power 3 then the reaction then the reaction will proceed in forward direction more value of KC more will be more will be the tendency to go in forward direction forward direction and the position of equilibrium position of equilibrium lies towards the product lies towards the product product side it will lie because KC value is huge it has high tendency to move into the forward direction. Okay now if KC value is less than 10 to the power minus 3 then the reaction has tendency to go in backward direction backward direction and the position of equilibrium of equilibrium lies on the reactant side the reactant side. If KC value lies in this range then the reaction can move in any direction see here we say it has more tendency to go in backward direction more tendency to go in forward direction if KC value lies in this range then the reaction has tendency to go in any direction forward and backward depending upon the condition. Okay right on the last point also same thing same thing KP also will have some other value of KP you need to find out correspondingly KP with respect to KC you need to find out but that value is not given if condition is given then you can find out KP with this value of KC minimum value you can take okay but that is not required if it is required you can find out all the conditions will be given like RT and all you can find out and that will be also for a given reaction because delta n is there no right on the last point if KC value falls in this range greater than this and less than 10 to the power 3 in this range the reaction has tendency to go in any direction depending upon the reaction condition next we have one more term called reaction quotient it is represented by Q write down it is a ratio of ratio of product and reactant at any point at any time write any time you can write down this so suppose we have a reaction A gives P D so reaction quotient Q is equals to we have concentration of D by concentration of A right at any time T at any time T any time if this T is equals to T equilibrium equilibrium then this Q is nothing but the equilibrium constant KC right so Q and KC we don't have any difference right KC is the specific term specific value of the ratio of product and reactant once the equilibrium is achieved right so we can write here Q is equals to KC which is equals to B by A B by A at any time where T is equals to T equilibrium this condition we have when T does not equals to T equilibrium yes same power of coefficient coefficient is there everything is same nothing changed here if coefficient is there this need to write down the power over there see yes one thing you understand we don't have a you know clause of temperature over here for any reaction we have a specific temperature and and that specific temperature we have a specific condition of equilibrium means specific concentration of reactant and product where the equilibrium is achieved right so for that particular temperature right when the equilibrium is achieved again Q is become Q is equals to KC we don't have the difference between Q and KC okay you are talking about in terms of that definition okay any temperature temperature is not a clause the point is once the equilibrium is achieved Q is KC right once equilibrium is not there then the ratio is Q right condition of temperature is not there we can have equilibrium constant of any reaction at any temperature yes we will share the TPP well okay one last you know term we will see over here that is degree of dissociation degree of dissociation alpha it is represented by alpha alpha degree of dissociation alpha is defined as the number of moles number of moles reacted divided by the number of moles initially taken initially taken it is always less than you know less than one it is always less than one alpha so suppose we have a reaction A gives obviously reversible reaction B plus C at time T is equals to zero its concentration is A there is no B or C present now I'm assuming at time T is equals to T right or T equilibrium for example X moles of A reacts or X concentration so this would be X this would be X because one mole one more one more we have right so X is the number of moles that reacts A is the initial moles we have total volume I am assuming one liter so when the volume is one liter moles is nothing but the you know the concentration so degree of dissociation alpha in this case would be what alpha is equals to X is the mole reacts divided by A this is alpha so X equals to what A alpha A alpha which we can substitute here so it becomes A minus A alpha it is A alpha and A alpha so what is the relation of KC is equals to concentration of B by concentration of C by concentration of A which further it becomes A square alpha square by A by one minus alpha which is equals to A alpha square by one minus alpha KC expression is this tell me and I show this so we'll do some examples on this how to write down the expression of KC next class on this okay we'll share one dbp that you can solve okay we'll wind up the session here see you in the next class okay get it out no yeah okay yeah thank you guys bye take care