 Next write down next metamers write down these are the compounds These are the compounds which has different group present which has Different group present the polyvalent functional group on the polyvalent functional group next time This is only possible in Only possible with the functional group with the functional group which has Valency Greater than or equal to 2 greater than or equal to 2 so Polyvalent functional group is required for this kind of isomalase Polyvalent functional group means what the valency is to our mode for example, you see ether To open bond we have valency is too, but if you talk about Antihide C double bond O H it is monovalent only one bond is open I'll be done also I'll be hide won't show I'll be hide cannot show metamers, right? Is also polyvalent function Right hio ether also a polyvalent function Amines are also a polyvalent function. Okay. We can also take C double bond O O R represent this is also polyvalent Okay, so this are you can exchange you don't write this as termation or you can actually Give you like that Now suppose the molecule is this CS3 CS2 O CS2 CS3 What is the name of this compound? Die ethyl ether Right die ethyl ether. What about this one? CS3 O CH2 CS2 CS3 What is the name of this compound? Die ethyl propyl ether Die ethyl propyl ether. They have same molecule formula Yeah, right Do you keep calling it propyl? No, no, no, no Methanite can use this just not a leaf It is C double bond O O R Yes Name is methyl propyl ether die ethyl ether Same molecule formula, right? But the Alkyl group across the polyvalent functional group, which is oxygen here ether Here we have ethyl ethyl. Here we have methyl and propyl different alkyl group is present. So these two are Metamersal feature right Ketone, they include double bond O. What is the name of this compound? Pentane 3-1 Right, pentane 3-1. What about this one? Pentane 2-1 So position is what? Here it is 3, here it is 2. You can ask me why this is not positional isomers Right, we can say it is positional isomers if metamers is not there in the option Priority is what? First metamers, if metamers is given, then metamers otherwise will take positional isomers Right Because the definition of metamers is more specific here okay, so These two are Preferably we will say these two are metamers of each other. If metamers is not given in the option Then we will go with positional isomers, correct? So right down here. If metamers Is not given in the option Then we will consider these as original isomers Original isomers, you see this example again This side we have finite, this side we have cyclohexane. If you exchange these two These two are again metamers of each other So Esther can also show metamers It is what? It is benzyne, cyclohexanoid No, just a second No, it's not This is a substituent, right This is one carburet and this is one carburet So it is cyclohexane, phenyl methanoid Cyclohexane, phenyl methanoid The link on a cyclic chain, both we cannot consider Here also it is benzyne, cyclohexane, methanoid But so these two metamers Name is this, they are metamers Cyclohexane, phenyl methanoid No, not phenol, cyclohexane, benzyne methanoid Why methanoid? Because we have only one carburet Next right down ring chain isomers Ring chain, right down in this type One of the isomers is acyclic and other one is cyclic One is open chain, other one is ring structure Ring chain isomers, okay Like propane to on, propane to on Propane to on is this Right, and this one Ring chain isomers, okay If you take this as propane type or cyclo propane Ring chain isomers, you can check the molecular formula is same for these compounds Okay, any other example? What if we take antihide here, CS3, CS2 This one right now, double bond O and H These two are also ring chain isomers These two are also ring chain isomers So one compound is acyclic, another one is cyclic Anything else? We have done structure, what else we have done? Totomerism Totomerism Totomerism will do it in the last We have done only as one isomers, so Totomerism will do that Sir, matter of course is oxa-cyclobuta Oxa-cyclobuta, yes Okay, okay, write down Totomerism Write down, this is, Totomerism is a definition This is a spontaneous phenomenon This is a spontaneous phenomenon in which two different compounds Two different compounds exist in Two different compounds exist in Dynamic equilibrium What is dynamic equilibrium? The constant Interchange, A B may be same The reversible reaction is where we have the equilibrium That is dynamic equilibrium So you see here, suppose we have this example Sir, isn't this business? Yes, it requires CS3, C double bond O, CS2, H Don't ask me why did you write this CS3 This is what, this is ketone When you take this compound into a container Or a vessel, you have pure This compound you have taken Initially it is 100% Because we have only acetone or this molecule present In the vessel, right? 100% After some time, if you measure the percentage content It's important There are a lot of exams There are a lot of exams Try to understand Try to understand again Okay, whatever we have done so far This is the most important part in the structure Okay, and its application Organic chemistry will go everywhere So this is initially 100% After some time, suppose 5-10 minutes If you measure the composition of this It won't be 100% Because some part of it will convert into this molecule Which is CS3, C, O, H Double bond, CS2 Okay, this we call it as enol En and all En stands for this double bond And all for this O, H Right? This is ketone Enol, automatism we call it Okay, it is keto enol, tautomeric Because the conversion of keto into enol This happens spontaneously We are not doing anything into it En, enol This side is enol Double bond, so En, O, H, so all Enol, right? So it is enol So it is keto enol, tautomeric What happens here? Because of this electron is drawing nature of this group These hydrogens are acidic hydrogens Okay, this hydrogen has tendency To come out as H plus When this comes out as H plus What happens here you see CS3, C double bond O, CS2 And negative charge H plus comes out, so you get this And this happens on its own Because the process is spontaneous Now we can draw the resonating structure here Because it is in resonance Conjugation is there So when you draw the resonating structure You will get CS3 C O minus double bond CS2 So you see we have two different sides Where this H plus has a tendency to attack Actually A H plus valid nickel band Then it also wants to attach on the molecule But when it comes out This molecule, some part of this molecule Converts into this due to resonance This H plus comes out You get this Now when this H plus wants to attach Again on the given molecule Some part of it in between Converts into this Now it has two different sides This H plus can attach on this carbon also And this oxygen also So if this H plus attached to this oxygen Will end up getting this molecule And if this H plus attached on to this You will get the horizontal molecule So the one which is more stable That will only form As a major problem in this reaction So here which happens It only generally more stable C double bond O bond strength is higher than Half L and B in all that Half L and B in all that Of course this and that These are intermediates Won't be as a problem You have this and this There are various, you know Factor we have which stabilizes these two So we will see that later One note you write down here One note you write down Because of the electron withdrawing nature Of this state The carbon hydrogen bond becomes very weak And then it comes out as Basically it facilitates the acidic behavior Of this So what process is there a electron on that? It is beta enol tautomeric So but then how is it changed Because of electron withdrawing nature of this This hydrogen becomes acidic Right It has tendency to come out as H plus However it is not a strong acid But some H plus will come out When this H plus comes out It converts into this Which forms this as a resonating structure And then H plus See it is just for your understanding Actually tautomerism one point to write down It is possible in both acidic Or basic medium It is possible in both Acidic and basic medium So next class we will see the mechanism first Okay We will see the mechanism first in both the medium And we will see how to decide Which product is the major product in various Differentia Correct