 बच़न लिग तुर आप से णए फोज़ुर ५ और असा सावस्चा, और आप से विर्वें आप off and we have done a little bit of nomenclature in Rajachinagaru also so that you can correlate or understand the facts of that we use in this. Uh, that we use in this somehow, somewhere we use in this particular chapter of isomerism, okay, so all of you have the basic idea of nomenclature, so I don't think you will feel much, much much difficulty, into this, but yeah. थेदूग बतटी आस्वमेर लगाव है, विस्टिनाव लगाव लाव है, शब्ती और आस्वमेर लगाव वो आप यार ठोगान दिल बाधा लेकान बतटी इस वी लेगतर मेहां। of isomerism like we are not we do not use but all these you know pharmaceutical industry if you see, whenever they produce any medicine and all they first try to understand the stereo aspect of one particular compound straight organic compound because when the structure of the organic compound changes is physical and chemical properties. Changes and that is what isomerism is okay. और वेजा का उर्द of codis okay it's a fact I suppose you see ice payroll is mciris means what ice money isn't is a phenomenon okay ice away s'amir is m is a phanomenon in which one Allah one particular molecule with one particular molecular formula can be represented in two odd many other different ways right and all these different different structure Than or that you can draw from one particular molecule gives you different physical or chemical properties of the same molecule formula right so first of all if you see the definition of this particular term that is isomerism and before understanding this isomer भी टल बी शुग दोगागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागागा� కివాదిగాయె roamain ఽాయెము Buddha ప� naucనినిస్లన Св ంపికికాసిసొ ాల౟నౄి సిాకుటి help మ взять స఼లుజ Catalunya ఆరెర్ల esperarVi ఇలాలుడబిని ఎబిలాధెయాకిత౤ా. and the existence of two or more structural formula of the same one one molecular formula is known as isomerism okay like suppose if I take one example here suppose if I write CH3CH2 OH and one more molecule if I write which is CS3OHCH3 आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आप आ� आप आप आ� आप आ� आ� आ� आ� आ� आ� आ� आ� आ� आ� आ� these are called isomers of each other. isomers you see isomers is only defined for a pair of molecule. this term is only defined for a pair of molecule. when I say isomers it means we are talking about two molecules, its not single molecule. its not the same of two molecules. In both of those, we are defining those isomers. but if we are talking about multiple molecules, If we say compound A is an isomer that does not mean anything值 isomer is the mixed part that we have to understand अंप्य़ोडी नौदोहटी याख मुन्रनी णीदरू ञाईताँ environmental 6 । आarre начинаák already करस्वि brutally अगर कर्च्वि heartfelt बा�你的 expressions अगर दख सदेर कहँत करनँर glasses वह जे की भी। रता. या पाश खोर is मनऔच दुद consciousness कर स introduction इं करक्चिस करक्ची की थी stays इं � hela फुर समकस transcend नों धिन ब़तके all these okay but everything is important right optical geometrical is the most important part in this chapter we have for j point of view right this one is the simplest part that will start with structure only today okay confirmation and optical also we'll see all these things one by one we have to study okay in this what happens in structural isomerism we usually say the connectivity of atom is different i'll just write down in the next page here the connectivity of the atom is different here the connectivity of atom in the space is different we are talking about three dimensional molecule here in case of stereo isomerism right in the space if the arrangement is different then we call it as stereo isomerism okay so first thing that will start here that you write down structural isomerism last two parts of structural is metamerism and tautomerism this is metamerism and this is tautomerism okay metamerism and tautomerism one more thing i forgot to tell you here see this tautomerism we will not discuss now because it requires some concept of reaction or the reaction goal it is actually a kind of isomerism in which two molecules are exist in equilibrium okay this tautomerism part we will not discuss now right this we'll discuss later on not today right when we study some basic concepts of reaction mechanism in that we'll discuss this tautomerism especially in goc right so next thing you write down that is structural isomerism just a second thing is just a second i'll start okay structural isomerism write down the definition here for structural isomerism this is this is the type of isomerism in which our groups that essential condition is what is that Bharath what is pt groups ring chain is also a classification that comes under functional isomerism shreya okay see ring chain also will discuss in this particular section only but that comes under functional isomerism i'll mention this later on understood shreya i'm not getting you Bharath what do you wonder what do you mean by this point groups let's see connectivity of atoms our groups are different you see like the first thing here for a compound for any compound to show or to have the relation of isomers they must have same molecular formula molecular formula must be same must be same that's the essential condition we have if the modern molecular formula is not same it means those two compounds are different compounds they are not identical right so whenever we are talking about two compounds suppose a and b and if we try to establish the relation between these two compounds relation means what whether these two compounds shows isomerism or not if they shows then what kind of isomerism they show whether it is chain position function or whatever right so to to establish or this kind of relation the first thing we should have that they must have same molecular formula right if they do not have same molecular formula the compounds are different then we cannot say that they exist or they have isomer relation isomer relation or something like that okay now in this you see structural isomerism the connectivity of atoms and groups are different meaning here it is what suppose if i write down this compound a is connected with b b is connected with c and c is connected with d right molecular formula is what of this compound it will be a b c d i am taking some general example a b c d right now if i write down the another structure of this in which we have a connected with c connected with b and connected with d for this one also the molecular formula is a b c d only right so you see the molecular formula for both compounds are same but the connectivity is not same here connectivity means what you see here in the first particular example a is connected with b only and b is connected with a and c c is connected with b and d right but when you compare with this compound which has the same molecular formula a is connected with c c is connected with a and b and b is connected with c and d you see here b is connected with a and c here and here it is connected with c and d so obviously the connectivity in these two molecules are different and that's why we say that there is a phenomenon of structural isomerism possible okay structural isomerism possible now like i told you that there are five six seven types of structural isomerism we have those are chain position and all right so one by one we'll discuss this because in the exam they ask that which of these molecules shows chain isomerism or position isomerism okay so the first part of it structural isomerism you write down the first type of structural isomerism is chain isomerism chain isomerism now like i said like i said that to show isomerism the molecular formula must be same now we are going to discuss chain position function and all so how do you identify that the given compound shows chain position or functional isomerism to understand that first thing that you should know that for that to show chain isomerism what is the similarity we should have between the two organic compound and what is the dissimilarity we should have these two information you must have right the first thing is what which is common in all type of isomers whatever we'll do whether it is structural or stereo the first thing is what that the chain isomers should have same molecular formula and this thing is common in all types of isomers any compound to show isomerism they must have any two compound to show isomers they must have same molecular formula right the first thing is this this should be common and for to to show chain isomerism they must have same functional group also same functional group and the third thing that you should know which is different carbon chain different carbon chain what do you understand by different carbon chain the number of carbon atom in the parent chain must be different that's the meaning okay different carbon chain means what the number of carbon atom in the parent chain should be different for example you see see if i write down this molecule ch3 ch2 ch2 ch3 what is the name of this compound n butane right it is n butane or simply butane iupc if you want to write what is the molecular formula of this suppose if i write down one more compound here which is ch3 ch ch3 and ch3 right this is two methyl propane two methyl propane see like this if you do not write this name also it's fine because we are not doing nomenclature here but in this organic ms3 you always get this kind of compounds in all the chapters so this nomenclature you can practice parallely whatever compound is there you just try to write down the name of that you don't require any so you don't have to go for separate you know practice session for nomenclature right whatever chapter you are doing you try to write down the name that is how you can practice nomenclature anyways coming back to this can you tell me the molecular formula of this it is c4 h10 does these two compounds have same molecular formula yes or no these two compounds have same molecular formula yes or no tell me molecular formula of this compound is also what c4 h10 you see this is the first an essential condition for any two compounds to show any kind of isomers right you see same molecular formula but number of carbon atom in the parent chain you see here it is how many carbon atom here it is four right straight chain and here the number of carbon atom in the parent chain is three only right three only so you see here same molecular formula there is no functional group and different carbon atom present in the parent chain so these two compounds are the example of what chain isomers here so what we call it as n butane and two methyl propane are chain isomers and this phenomenon is chain isomerism is it clear tell me quickly okay see another example here here we have OH and CS3 what is the relation of these two means what kind of isomers it shows see here also you try to compare this how many carbon atom we have here one three four five the name of this compound is what two pentanol right it is two pentanol the name of this will be what one two three four right two methyl butane to all right so again you see here molecular formula of this is what excuse me molecular formula is one two three four five so it is c5 h h 12 oh i guess and for this also the molecular formula is sorry c5 h 12 oh molecular formula is same and the functional group is same number of carbon atom in the parent chain is different so this is also the example of chain isomers right see there is one more thing here like and this this this thing you listen to me carefully sometimes it is with few examples it is sometime difficult or confusing to understand like this everything you have to check to do this whether it is chain or position isomerism that we'll discuss after this what we'll do we calculate isomeric number so this is a trick we are using right and the trick is what we will calculate isomeric number isomeric number now what is isomeric number it is x y isomeric number is x y now what is x write down x is the number of carbon atom in the main chain number of carbon atom in the main chain and y is the number of carbon atom okay y is the number of side chain the number of side chain starting with carbon with carbon so what you have to do just you can find out x and y and you write it down there okay like you see here for this compound and the thing is what for chain isomers this also you write down for chain isomers the number of the isomeric number isomeric number must be different the isomeric number is different for the two compounds with provided what provided they must have same molecular formula right with same functional group right so if the isomeric number of two compounds provided they have same molecular formula and functional group are same then those two compounds are known as chain isomers right now how do we find out this isomeric number you see in this one for this the first one n butane if this isomeric number x y you have to find out what is the value of x here the number of carbon atom in the main chain that is 1 2 3 4 we have x value is 4 and there is no branch present into this so y is 0 so isomeric number of n butane is 40 is it clear is it clear how do we calculate this isomeric number if not then you can ask me so you tell me what is the isomeric number of this compound tell me the isomeric number of two methyl propene who is this vigi plays please type in your name the use i will tell you krishna wait okay so the number the value of x is the number of carbon atom in the parent chain that will be 1 2 and 3 so we have 3 and there is one side chain starting with carbon atom that is important you see number of side chain starting with carbon atom right so that will be 1 so x y value is 1 so now you see when you have this isomeric number right and the two molecule has same molecular formula this is what you have to check molecule must have same molecular formula right two molecules having same molecular formula and different value of isomeric number which is x y so when the two molecules having same molecular formula and different isomeric number they said to be chain isomers is it clear now krishna you will feel like okay why this thing we are calculating we can directly look at the molecule and say right whether it is chain isomers or not yes or no how many of you are thinking this how many of you are thinking this that we don't require this we can look at the molecule itself this will check the number of carbon atom in the parent chain and then we can say it is chain isomers or not how many of you are thinking this that this isomeric number is not required i've been fast okay so whatever you are like whoever thinking this that this is not required just give me some more time you will understand the you know uses of this because these are very simple compounds okay they come the example that i have taken here right yeah fine these are very simple compounds actually say in in the exam they won't ask you these compounds but for other compounds i'll give you the examples there we have this thing is useful isomeric number okay that's why we are doing this anyways so we'll do that tell me the isomeric number of this compound these two tell me the isomeric number of this fast sushant it won't be difficult later if you understand it properly at least this part is structural part is easy okay so for this one the value of x is five and there is no side chain starting with carbon right so y value is zero so it is 50 and for this one x y value is four this is the value of x and for y the value is one 41 do you see two different compounds with same molecular formula same functional group having different isomeric number hence they call as what chain isomers of each other it's okay they've lost okay 50 and 41 so these two are also chain isomers of each other fine can we move on now next thing next the second type of structural isomerism we have that is position position isomers now in this you see again what is the for two compounds what is the condition we have to check to understand whether they are position isomers or not that is what i'm i'm not giving you the definition here definition you will get it in the book but that won't help you in solving the question so the key points that is required to identify whether the molecules are position isomers or not that i am giving you the first thing here you have to write down here you write down the two molecules if they have same isomeric number same isomeric number then they are said to be position isomers right same isomeric number you should have now what is the similarity we should have in the two compounds the first thing is again the same molecular formula they must have same molecular formula they must have same functional group same functional group third one we have same parent chain means the number of carbon atom in the parent chain must be same same parent chain and the last one different location of different location of double bond or triple bond functional group if it is there functional group or substituents welcome so good anyways so different location of the substituents right double bond triple bond functional group or any substituents okay so these are the four condition we have for position isomers okay and apart from this four one thing that always helps you a lot in finding out position isomers that is same isomeric number now you see the example here if i write down this one what is the name of these two compounds i guess all of you can write down the iso iopc name you see the molecular formula for both the compounds is same c4 h9 cn right c4 h9 cn see same parent chain when you say adhvet it means we should have equal number of carbon atom in the parent chain in two different molecule means number of carbon atom in the parent chain you cannot change otherwise it will be chain isomers not position isomers you see here also 1234 you also 1234 carbon okay same number of carbon atom in the parent chain for two different compounds with same molecular formula and only the position should be different here you see if i if you try to write down the name of these two compounds will start will check the parent chain is this and then we numbering this 1234 for this it will be 1234 the name of this will be what two chloro butane right and for this it will be one chloro butane right so in these two compound you see molecular formula is same the only difference is what that the position of chlorine is different okay so position of chlorine is different so it will be what it will be chain isomers of each other now you tell me the x y the form the number isomeric number is what for these two molecule you tell me the x y of this and x y of this isomeric number that will be what four carbon so 40 and four carbon so 40 you see the two molecules have same isomeric number and hence they are position isomers another example you see these two you see the position of double bond is different if you write down the numbing here 12345 12345 the name of this will be what it is pentene pent 1 in or simply pentene and this one is what pent 2 in right so position of double bond is different if you find out the isomeric number that will be 50 here and 50 here so isomeric number is same molecular formula is same hence the compound is what position isomers one more example you see if i write down ch3 ch2 c triple bond ch and ch3 c triple bond c ch3 you see the molecular formula of this is what c4 h6 and it is c4 h6 same molecular formula only the position of triple bond here it is at first carbon and here it is a second carbon if you find out the isomeric number that will be 40 isomeric number that will be 40 same isomeric number positional isomers if there are two functional group like oh and cl in two different compounds only the location of cl in the first see the compound see the compound let me give you one example here like like this you will get confused see if you have this compound one two three four five you have chlorine here right and another compound if you write one two this and if you write down chlorine here see these two compounds are what they are isomers of each other or not they are isomers of each other is not are not are they isomers of each other what relation they have any one of you can you tell me the name of this compound and what is the name of this compound the two compounds will be same or different depending on their name if the name is same the compound is same you see for this one if you write down the first one will be one two three four five and six so it is two clodo hexane correct vrat two clodo hexane and for this one if you write down the numbering one two three four five six this is also two clodo hexane two clodo hexane so basically these two compounds are identical compound they are not isomers of each other right so whether the two given compound whether the two given compound is different or same that depends on their name if you write down one more compound like this you see one two three four five six and if chlorine is here then this is three clodo hexane so this one and this one are position isomers of each other because it is two clodo and this is three clodo hexane only the same substituents in both compounds cannot be the same position in the same position but different substituents can be in the same position like see we see the position of chlorine and hydroxy group separately no if you have one overt group is present at second position if see that there are only two i'm not actually getting your ashtos properly but if you have any doubt in whether the compound is same or different if the name is same then the compound is same that's the only thing whatever the two compound you have with the position you write down the name of that compound if you are getting same name with same position of substituents then only it will be same yeah you better you ask me in that class okay chalo so you see some examples i'm giving you here and you have to identify that whether they are chain or position isomers okay so one by one i'm writing it down you just tell me once you finish it the first one is just a second yeah it's mitha can you want me tomorrow or after 7 30 because i am busy in love this normality same number you can watch it okay yeah so the compound is this this one this there's one methyl group here right and this one tell me first one yeah just you write down the name whether chain or position same position chain position position position position you see this one and these two both compounds are same the isomeric number of the first one is 41 and the second one is also 41 but the compound is identical they are not isomers of each other this is also two methyl butane this is also two methyl butane okay so the x y value is same and the compound is said to be identical so you must take care of one thing when the isomeric number is equal then you have to check that with that the whether the compound is identical or not if not identical then it is position isomers okay so these two compounds are identical again this one you see for what is the value of isomeric number for this is it 32 and for this it will be 32 same number three carbon in this ring the parent chain in this reward will be this ring three atom and we have two side chain with carbon two side chain with carbon so x y is 32 and this is what this is positional isomers this is positional isomers for this one x y value is what 41 sorry x y value is 51 and for this x y value is again 51 position of this methyl group you see the number of carbon atom in the parent chain is 5 and 5 x nothing but the number of carbon atom in the parent chain right so 5 and 5 is equal position of this methyl group is different so this is also positional isomers what about this one this one is also you see that if you write down the name of this it's x y or isomeric number will be 40 and its isomeric number will be again 40 this is cyclobutene this is also cyclobutene so the molecules are identical this one you see this one the numbering will be like this one two three four five and six and for this it will be one two three four five and six x y isomeric number for this compound is what 60 isomeric number for this compound is 60 equal isomeric number but different position of double bond here it is at between four and five here it is at three and two three and four right the different position of double bond same isomeric number example of position isomers right in this one what is the answer of this one for this question what is the answer what is the name of this compound so only r m one is correct in this you see here the numbering will start from this carbon one two three four and here the numbering will start from this carbon one two three four and five so here we have five carbon atoms in the chain and here we have four carbon atoms in the chain the name of this will be two methyl butane nitride and for this will be pentane nitride okay it's not cyanobutane have you rnr guys have you finished this nomenclature of sino group nitride yes or no have you finished this nomenclature of sino group that's why you are wrong anyways anyways so you understand one thing when you have cyanide group present then we always start numbering from this carbon atom carbon atom of the functional group we'll discuss this tomorrow also in the class yeah it is a functional group so for this functional group we always start numbering from this carbon that is the rule we have yes sino group c is counted in the chain so one two three four we start we start from here and try to get the longest possible chain so here we have four carbon here we have five carbon number of carbon atom in the parent chain is different molecular formula is same so it is a chain isomers okay now for this one you see molecular formula is same the value of isomeric number is 40 and here the value of isomeric number is again 40 or it's 50 right and this is also 50 so it is position isomers of each other position of OH group is different what about this one what is the value of x y 61 x y 61 same isomeric number we'll start counting numbering from this carbon one two three four like this we go and here we'll start from one two three and four right so the position of double bond is different here it is a third carbon and here it is first carbon with equal isomeric number so it is position isomer yes where is nitro sriram where is nitro there is no NO2 group present it's OH hydroxy and all of you done okay i'll tell you tomorrow nitro is NO2 okay okay few more examples we'll see see in this one i'm giving you three structure which is this first one this is A and C what is the relation of AB A and B what is the relation A and C what is the relation B and C what is the relation okay so position chain and chain you see what is the isomeric number of this one A x y it is 62 this is 62 and x y is 61 right so A C and B C are these two are chain isomers different isomeric number A C B C has different isomeric number chain isomers AB is position isomers see we have two subs two substituents into this two functional group what kind of isomers these two are or they are isomers or not are they isomers if yes then what kind of isomers what is the molecular formula of this 1 2 3 4 5 6 6 carbon right so C 6 3 4 5 6 7 9 plus 3 12 H 12 oh this is the molecular formula for this one it is 3 4 5 6 7 8 9 10 11 12 so C 6 H 12 oh right same molecular formula molecular formula you must check right so when they write down the name of this compound you will start numbering from the left carbon because OH we have to give the priority so we'll do from 1 3 4 5 and 6 and this is 1 2 3 4 5 and 6 you see the name of this will be hex 3 in all and this e you have to drop and here we'll write hex 5 in to all and this e again you have to drop you see the position of double bond is different and hence it is a pair of position isomers two substituents is here you can have any other chlorine also present here here or here then also you will do the same way i hope you will understand now okay in this one what is the value of isomeric number 60 what is the value of isomeric number x y 60 you see same isomeric number we have position isomers understood now see just you go through the name of this first of all if see the logic here is what the first thing molecule formula must be same yes it is same right x y value is equal so equal so that's why it is position isomers if one substituents the position of one substituent is same but the position of other one is changing so with respect to that it is a position isomers if it is same in both then it will be identical compound if the position is same so both name will be same identical okay so now you see this one this one and this one what kind of isomers these two are and after this two more we'll see i'll write down here the next one example in the last one we have what about the first one the first one you see the molecule has same molecular formula it is very clear from this six carbon and here we have six and four ten carbon six plus three nine and one ten carbon so molecule formula is obviously same that you have to check first right molecule formula is same what is the x y number of this isomeric number of this compound and isomeric number of this compound in these kind of compound we call it as bi cyclo compounds okay i will discuss this tomorrow in daljeenagar this is bi cyclo compounds so in bi cyclic compounds it is easier to check this isomeric number so in this the isomeric number will be what how many carbon we have 1 2 3 4 5 6 7 8 9 10 total x value is 10 and there is no chain into this so that is 0 100 x value is 9 here and there is one chain so 91 molecule formula is same isomeric number is different as these are chain isomers right how it is chain so get the last two this one you see only the position of double bond is different here x y value you can calculate you'll get the same into this x y value is what it is 100 and for here also x y value is 100 same molecule formula equal isomeric number it means it is position isomers and clearly you can see from the molecule the position of double bond is different for this x y value is what it is 63 and for this it is x y value is 62 different isomeric number it cannot be position it is chain understood now so when you calculate this isomeric number this will be easier to identify can we move ahead now next right down there is one kind of question that they ask which is number of mono substituted product we have to find out no just you have to find out you see if you have to find out x y value you only need the number of carbon atom in the parent chain that is x plus how many side chain or substituents we have starting with the carbon atom right so in the side chain number of carbon atom you don't have to find out you see this one i'll go the previous slide once you see in this one we are not counting these two carbon here we have just counted okay one substituent is this starting the car so this whole is one and this whole is one so that's why six in this ring and one plus one two here you see this whole is one two and three that's what is 63 i have a bit scared now next you see the number of one question that they ask into this that is number of mono substituted product you have to find out number of mono substituted product mono substituted product means what only one substitution is there means only one hydrogen is replaced by the any other element so you see here first of all if i take the example of butane and suppose butane is c4 h10 butane is c4 h10 right so the question we have to find out how many monochloro products we get okay and the question is with this compound how many chlorine you have to add into this molecule one hydrogen will come out and one chlorine will attach onto that carbon atom from which the hydrogen is coming out try to find out this i can't see your comments just a second yeah okay so answer is adwet is saying five shravan six or five tell me one answer shravan and most of you are saying two two monochloro derivative derivative who is this busy place type in your name please yash ketan is saying six oh it's gaurav that's what i was thinking anyways okay you see so butane we have so see first of all you have to understand and okay now i am explaining okay is someone is saying five six and all okay first of all you have to draw the structure of butane cs3 ch2 ch2 ch3 this is one possible structure of butane or we can also draw this structure cs3 ch cs3 cs3 isobutane sorry right these are two structure possible now in this you see there are two different position we have you try to understand this okay there are actually two different position we can add one chlorine see this carbon is what this carbon is one degree carbon this carbon is two degree carbon this is one degree carbon and this is two degree carbon so we can add chlorine any one of these two carbon at me you see the possibility here it is what we have one possibility is what and here also there are two possibilities this carbon is one degree this carbon is one degree this carbon is one if you add chlorine onto this carbon atom will start numbering from this side so both product will be same yeah i'll give you some first you understood this one or not you tell me so in this question the number of possible monochloro product is four the answer will be four right now the second thing what kind of isomers these two are coming back to the isomerism part right what kind of isomers these two are and what kind of isomers these two are tell me okay you see how you can do this this is chlorobutane this is two chlorobutane so obviously the position of chlorine is different so these two are positional isomers x y value isomeric number you can find out here also you can isomeric number find out this is one chloro two methyl propane this is two chloro two methyl propane position of chlorine is different these two are also positional isomers understood all of you this see in this in this type of question they can ask you many there are many permutation and combination here they can also ask you how many positional isomers will get here there are possibilities that some of the compounds will be position isomers and some of the compounds will be chain isomers like that okay so they can ask you how many compounds are positional isomers how many compounds are chain isomers what is the total number of product also anything they can frame okay so the total product the answer will be four the number of iso position isomers is also four in this case but depending on the components and molecules the answer can be different also is it clear this question you tell me c h 3 c h 2 c h c h 3 and c h 3 here right in this how many monochloro product we can get how many monochloro product we can get tell me shushant just a second give me a second i will start just a second so what is the answer how many products we get here this carbon is one degree right and this carbon is one degree and this carbon is one degree so these three carbons are one degree carbon and this one is two degree and this one is three degree carbon now when you see here there are different different group we have so in this one you see if i add i can add chlorine here right i can add chlorine here or we can add chlorine onto this carbon also or we can add chlorine here also and at this position also right if you add chlorine add to this carbon then this carbon and this carbon is identical but this carbon and this carbon is not identical however they are one degree carbon you see here the structure that we get see the possible structure if i write down here it will be c h 2 c l c h 2 c h c h 3 and c h 3 plus another possibility is what we'll get this c h 3 c h c l c h c h 3 c h 3 another possibility is what we'll get this c s 3 c h 2 c c l c h 3 c h 3 and the last one is c s 3 c h 2 c h c h 2 l and c h 3 okay so you see if you compare these two compound the name is different this is one clodo one clodo two methyl butane right and for this it will be one clodo so one clodo three methyl butane so name of these and these compounds are different however these two carbon are one degree carbon but because of this c s 3 present here these two carbon gives you two different product and the answer will be four yes most of you have said four answer will be four okay so now the thing is what you don't have to draw this structure every time in the exam like suppose in this one the last one like this will do suppose the compound is this right and we have one methyl present here methyl cyclopentanitis how many product possible just you have to look at the molecule and say you see this carbon if you add cloding you will get one product this carbon if you add cloding you will get one product this carbon and this carbon is identical right this carbon and this carbon is identical and this carbon and this carbon is identical so whether you add cloded onto this carbon or this carbon the product will be same or this carbon or this carbon the product will be same right so you see the answer for this one तfferential isomers, the condition in this you have to check is this. तfferential isomers the first condition. is same, that is same molecular formula. molecular formula, conjunction no formula why you need formula. तfferential isomers we must have different functional group , different functional group एकने थो अगिंत धूऍ कर्ईटब सले, tablet, लग्टक जाड़। � Xing़्ह्ती् हे गцर्द на ममानी फ्म्नच्छने सक है उआप टर्टी चो उऎन सक हैदा ठी स्बथोति कहिक लग्ट मी बोझा हो लिएद म았는데 अस लग्टक lack剉ट दिनसे कर्घ सी complete Indiana Spina but that helps you more in the case of chain and position isomerism. Okay, that helps you more over there. Here you have to check only the difference or only different functional group you have to check here. So here you see in this case, alcohol and phenom, you see whenever, see how do we understand the phenom विनाल is again the same example I will take, बेंजीन दिंग, here we have CH3 and OH and if I write down the another molecule in which the ether linkage is there, OCH3. Right, so this also, this is ether and this is phenol. So phenol ether you see molecular formula is same, you can check the molecular formula, it is same. Third one you see, sorry fourth one amines, amines okay. Two things are here, these are the derivative of ammonia, derivative of ammonia, this slight little bit information I will give you in a nomenclature tomorrow class okay. Ammonia is NH3, derivative of ammonia means what when one of these hydrogen you replace by any alkyl group R, then you will get RNH2. If two hydrogen you replace it will get by R2NH, three hydrogen you replace it will get R3N, this is two okay. So when nitrogen, this nitrogen contains two hydrogen or one alkyl group, then it is one degree amine okay. When the nitrogen contains two alkyl group it is two degree amine, when it contains three alkyl group it is three degree amine okay. So all these one degree, two degree, three degree amines are functional isomers of each other. You see example here, suppose if I write down this example CS3, CH2 under this only, under amines only, CS3, CS2, CS2NH2 two hydrogen here with one lone pair. Another example if I write CS3, CS2NH, CS3 and one more example will write CS3N, CS3, CS3. In all these example you see the molecular formula of this will be what 1, 2, 3 carbon. How many hydrogen, sorry how many hydrogen we have CS3, 3, 5, 7, 9, H9 and N, CS3, H9, N. If you calculate the molecular formula of this it is also CS3, H9, N and for this one also CS3, H9, N. So this is one degree, this is one degree amine, primary amine also call it as second degree amine, secondary amine or three degree amine or tertiary amine okay. So these three molecules are functional isomers of each other. Molecular formula is same, one degree, two degree, three degree amine are functional isomers of each other okay. What about these two you tell me, whether these are functional isomers or not? CS3 and CS3. One thing also you see here, one degree, two degree, three degree amines are functional isomers. One degree and one degree amines are not functional isomers. One degree, two degree may be, two degree, three degree may be. Means different degree we should have. So is this functional isomers or not these two? And one more if I give you and CS3 and H here. No CN is not an amine Sridhams, CN is Sino group, Sinide okay. We will discuss this tomorrow okay. CN is nitrile also yes, in IPSE name we will write nitrile also. Sino group, Sinide group, nitrile. Tell me this one, these two are functional isomers or not these two? See this nitrogen is three degree and this nitrogen is two degree. Nitrogen contains one hydrogen you see, nitrogen contains one hydrogen two degree. No hydrogen then three degree. So here we do not have a hydrogen with nitrogen right. So these two are functional isomers or not? First one is saying first one is functional, second one is no. Yes, no okay. So this one obviously it is functional isomers, yes. For this one the molecular formula is not same right. You see the molecular formula is not same. So these two compounds are not identical. Not same compounds, not identical compounds. And when the molecular formula itself is not same, we cannot define isomers. Correct, that's the thing. But what happens Sukirt, if I write down one more molecule like this, you have to compare this and this B. Is these two are functional isomers? So this one is saying yes. Shravan yes. Sukirt not functional. Sushant is saying yes. Bharat is saying yes. Bharat what happened to Sukirt? Okay, now Sukirt got it. Everyone is saying yes. Okay, functional. Fine, so you see because the molecular formula now it is same right. And this nitrogen is one degree and this one is two degree. How do you identify primary and secondary amines? Just you check the number of hydrogen attached with the nitrogen. If it is two, one degree, if it is one, two degree, no hydrogen, three degree. Okay, one and two degree. Anyways, so we'll move on. Next example we have the fifth one. See all these examples you have to memorize which all functional group shows functional isomers. Okay, so you have to memorize. Sometimes they ask this question directly in the objective. Which one of these pair of these functional group does not show functional isomers or show functional isomers like that. Okay, the next one probably the fifth one we have that is carboxylic acid and esters. Okay, so first of all let me tell you carboxylic acid. I have done this in HSR but RNA I will do it tomorrow. Carboxylic acid is this group when you have COOH group present then this is carboxylic acid which can write it as like this C double bond O and OH. If you know this fine I'll just I'm just giving you this information. Ester is this if this H you replace by alkyl group C double bond O OR then it is ester. Okay, these two group also shows these two group also shows functional isomers. Okay, for example you see if I write down this compound that is CH3 C double bond O OH. The IUPAC name of this one will be one to ethanoic acid IUPAC name of this. I will do this tomorrow. Okay, so this Rajinagar guys you don't get panic if you're not getting it. Okay, if you're getting it it's fine. IUPAC name is ethanoic acid. Okay, common name is acetic acid. This is very common acid you will get it everywhere probably in organic chemistry. So you must remember this name acetic acid CS3 COOH. But this has nothing to do with the concept we are discussing now. This is one particular compound and if I write down this one you see HC double bond O O and CH3. This hydrolyzed substitute here and CS3 I'll put it here. So obviously you see the molecular formula of these two compounds are same. Now it becomes COOR so it is nothing but ester COOH. So it is nothing but carboxylic acid. So this becomes ester and molecular formula is same. So these two are said to be functional isomers of each other. I hope it is clear. One more example if I can show you the example is this OH and this is double bond O. So this is what this is COOH acid and the another example if I write here oxygen and CS3. Here we have double bond O. So these two this one is ester COOR this one is ester and this one is carboxylic acid. Molecular formula you can cross check it is same. So these two are also functional isomers of each other. Next functional group which shows functional isomerism is this that is amide. Amide functional group is this it is C double bond O NH2. This group is amide. Whenever you see this group the name is amide. Like you write down 1 degree amide 2 degree amide 3 degree amide. Similarly we also write down 1 degree amide 2 degree amide 3 degree amide. Everything is same here. Like suppose if I write down the same kind of example CS3, CS2, CS2, C double bond O like this. So this is 1 degree amide. Nitrogen has two hydrogen here. So 1 degree amide. Next one you see CS3, CH2, C double bond O NH3. So this is 2 degree amide. And again if I write down CS3, C double bond O N CS3 and CS3. So this is 3 degree amide. Tertiary amide. All these 1 degree 2 degree 3 degree amides are functional isomers of each other. The same way that we have done for amides. So amide also shows functional isomers isomerism. Understood? Next one you see 6, 7 whatever the number you just put it down. Next one is aldehyde and ketone. This is very common. You must have done it. Aldehyde ketone in 10th class also. So aldehyde and ketones are functional isomers of each other. For example you see the simple one CS3, C double bond O CS3. And CS3, CH2, C double bond OH. So aldehyde is what? Aldehyde is CHO group. This group you see. Aldehyde is this group C double bond OH. This is aldehyde. When we have hydrogen present one side. Ketone is when we have C double bond O group present. And here must have some alkyl group R or R dash whatever it is. So aldehyde and ketones are functional isomers of each other. Provided when they have same molecular formulas. Next one is cyanides and isocyanides. Cyanides and isocyanides. Cyanide is this. It is C triple bond N. This is cyanide. And isocyanide is when you have NC. The coordinate bond N and this is here. Isocyanide is this. See the meaning of this is. This N is attached with the primary chain in isocyanides. In cyanides carbon will attach with the primary chain. For example you see this one CN NC. This nitrogen is attached with this primary chain. And this carbon is attached with the primary chain. So this is what this is the functional isomers. These two are functional isomers. These two are functional isomers. You can easily check that the molecular formula is same for this. Another one you see. I am doing some miscellaneous one also. These thing they will never ask in board exam. So I am just giving you every possibilities that we have in this. Nitro with nitrite. Nitro is NO2. And double bond O and O. This is nitro. And double bond O NO2 in short. Nitrite is ONO. Oxygen will attach with the parent chain. Here this nitrogen will attach with the parent chain. For example you see if I write down this one CS3N. Double bond O and this will write CS3O. And double bond O this one. Again you see in these two the molecular formula is same. So these two are also functional isomers. So nitrite, nitro and nitrite may also show functional isomerism. Just a second. Just a second. Okay guys we will do one thing that I will just take a 5 minutes break. It is 6.35 we will start in 6.40. I have got some work just 5 minutes break we will take and then we will start in some time. Just type in yes. Can we start are you there? So nitrite, nitro and nitrite also shows functional isomers. Next one you see. Next example is enol. The next one is enol and ketone. See this enol and ketone means what? En stands for this en stands for double bond that is en and ol stands for OH that is hydroxy group which is nothing but alcohol. So if I write down this compound you see CH2 double bond, CH single bond CH2OH and this compound CH3C double bond O. CH3. So this one you see the molecular formula for this will be C3H6O and for this one it is again C3H6O. So this is enol and this is ketone. Enol why because we have double bond for that it is en and OH also. Enol ketone also shows functional isomers. Another example of this if you see we have a molecule like this OH and double bond. So this is enol right enol we have this double bond O enol and ketone. Molecular formula is same here. So hence it is also functional isomers. Next we have last two also into this. The next one is dien. Dien means two double bond present. If the molecule is this this one you have triple bond. These two are also dien and alkyne. Molecular formula is C7H12 and here also it is C7H12. So you see same molecule formula with two double bond in one compound and one triple bond in another compound. So these two also functional isomers. So this is it for functional isomers isomerism. All these examples you have to keep in mind for functional isomers. What all compound shows functional isomers. Next in this function also we have one more isomers that we actually count in functional isomers. Only and that we call it as ring chain isomers in isomer ring chain isomers write down. It is due to it is due to the different modes of linking. One compound will be in the ring form and other one will be in the chain form. For example you see if I write down this one CS3CH double bond CH2. And if I write down this with this compound cyclopropane. If you check molecule formula is same. One is ring other one is one is ring other one is chain. So this is ring chain isomers. This one you see CS3C triple bond CH right. This will be this these two are again ring chain isomers. For butene bute one in this one CS3CH2CH double bond CH2. For this we can draw this structure. This is also ring chain isomers or we can also draw this one. Here we have CS3CH3 ring chain isomers. All these are ring chain isomers. Now one note you write down here which is important. One note you write down into this. See just to listen to me one thing first. Suppose this question is given right. And in the option ring chain isomers is not mentioned. Since what we do this ring chain isomers. So we consider it as a special type of functional isomers. Ring chain isomers are the other type of functional isomers only. So if in the option ring chain isomers is not given. Then we'll consider this as a functional isomers right. Otherwise if ring chain and functional isomers both are given in the option. Then we'll prefer ring chain first. So ring chain is that specific and more like specific answer we have. But if ring chain isomers is not mentioned in the option. Then we'll go with the functional isomers right. If both have been mentioned ring chain and functional. Then we'll prefer ring chain isomers into this. Okay that point you write down. If ring chain isomers is not mentioned. If ring chain isomers is not mentioned. Then we consider this into functional isomers. Then we consider this into functional isomers. Next one write down metamers. Metamers you write down. It is possible only with polyvalent functional group. What is polyvalent functional group? What is polyvalent functional group? Tell me what is polyvalent functional group? No you see polyvalent functional group means whose valency is more than 1. This polyvalent means what? Valency of the functional group is greater equal to 2. Equal to 2 also we can consider. So metamers only possible when we have polyvalent functional group. For example you see. Example of polyvalent functional group you see. Like when you write down ether. Ether is nothing but this. This is what ether. It is a polyvalent functional group because it can attach with this side also and this side also. Polyvalent. If you have this ester. This side also it can attach. This side also it can attach. Amines. Polyvalent. Ketone. Polyvalent. Which is C double bond O. NH. Polyvalent. Few examples you see. If I write down this. Any halogen group X. Fluorine, fluorine, bromine, iodine. OH. NH2. All these are monovalent. Why it is monovalent? You see only one bond is open here. Only from this side only it can attach. All these are monovalent not polyvalent. Monovalent functional group. So in all these group metamers we can explain. So in this you write down metamers are the compounds. Metamers are the compounds having. Metamers are the compounds having. Having different group present. Different group present across the polyvalent functional group. Different group present across polyvalent functional group. With identical molecular formula. Identical molecular formula. Now with example you will understand this. First one you see. If I write down CH3 CH2. CH2 CH3. CH3 OH. CH2 CH2 CH3. These two compound you see. Now in this one. Now in this one you see. You have to just compare the group which is attached to the polyvalent functional group. One side it is ethyl. Other side it is also ethyl. So if this group is different in the other compound. Then they are said to be what? Metamers of each other. Like you see if you compare this group left hand side it is ethyl here. But here it is what? Different group. Right side again it is ethyl. But here it is what? Propyl. So here it is methyl propyl. And here it is ethyl and ethyl. Molecular formula of both the compounds are same. Molecular formula of both the compounds are said to be metamers of each other. Is it clear? Yes or no? This one you see. H C double bond O. O CH2 CH3. And the another compound if I write. CH3 C double bond O. O CH3. You see. This is the polyvalent functional group. Polyvalent functional group is this. And this. So one side we have hydrogen present. Here we have CS3 different. Other side we have ethyl present. Here we have methyl different. But molecular formula is same. Ok I will repeat just once. We will do some more examples right now. Just wait. What I said that like you see this example for the second one. The polyvalent functional group is this. COO. This one. This one I am taking now. COO. This polyvalent functional group we have hydrogen. And other side we have ethyl. Excuse me. Another example you see. One side we have ethyl. Sorry methyl. And other side we have methyl. You just compare the group on the left hand side. And the group on the right hand side one by one. So on the left hand side we have CS3. But here we have hydrogen different. Right hand side we have CS3. Here we have C2 as CS2 CS3 different. So these two are also what? These two are metamers of future. In this one I explained. This side we have ethyl. But here we have methyl. Here we have ethyl. Here we have propyl. But the thing is what? Molecular formula must be same. So if you compare the molecular formula of this one. And this one it is same. This one this one it is same. That's why these are metamers of future. Ok what about this one? These are metamers or not? Oh sorry this one is not there. Metamers yes or no? Yeah you can say. This is also metamers. Now one more example I will see in the last one. These are metamers yes or no? Metamers yes or no tell me. These are metamers right? Ok everyone of you are saying yes. Now tell me one more thing here. What is the IUPSE name of this? And this. IUPSE name you tell me. So the first one is 3 pentanone. And the second one is 2 pentanone. And this is 2 pentanone right? Now what do you understand by this when you write 3 and 2? When you write 3 and 2 it means the position of keto group is different. Fine. Position of keto group is different. It means it can be positional isomers also. Why can't we take this as positional isomers? Can we say? The position of keto group you understand my question the position of keto group is different in both the compound. Then we can consider this as positional isomers also. Ok so the point here is what now you listen to me. Now you listen to me carefully. Whenever you have polyfunctional group attached to different groups on the other side then we always prefer to say metamers not positional isomers. Ok So for this compound suppose if the options are given first is chain second is position third one is metamers and fourth one is ring chain suppose like this. There are four options given and what kind of isomers these two compound shows always go with metamerism or metamers not positional isomers. Whenever metamers like we have in the case of ring chain and functional isomers if ring chain is mentioned we will consider ring chain otherwise functional right. So metamers whenever the polyvalent functional group attached with two different two different what we say groups right. Then we always consider this as the metamers not positional isomers ok second case if you imagine if this option is not given right if metamers is given we will go with this only. If this option is not given and we have some other option here none of these or something like that then we can choose position isomers is it clear. So basically we will prefer metamers if metamers is not mentioned then we can go with position isomers understood. So we are done with structural isomerism today in this we are left with tautomerism or tautomers so we will discuss it later later when we do some reaction mechanism ok some reactions thing we will discuss discuss this letter so this tautomers you let it be known tautomers in which both compounds may exist in dynamic equilibrium isomers exist in dynamic equilibrium so this you will not understand this now just you let it be for other classes right now the next thing we have to discuss here is stereochemistry right ok just you solve these questions first ok so we will see the question let us send you we are not getting it now anyways so next one you write down stereochemistry stereochemistry stereoisomerism stereoisomerism ok stereoisomerism is what it is due to the change in property of the molecule due to the relative position of atoms or groups present in the space right so we are talking about yeah tautomers is ok this is right tautomers is not keto in all tautomerism we have 4-5 examples into that ok so there are many things to discuss into that so that is why we are not doing it now and for that you require basic idea of reactions ok so we will do it later now you see here stereoisomerism and why it is important like one example I will give you here first of all the difference in stereo and structural isomerism is what in structural isomerism we will discuss the molecules or the relative position of molecules in the plane in a given plane in which the molecule is right but but you see if I write down one compound ok first you write down the definition of this stereoisomerism stereoisomerism is the study of stereoisomerism is the study of the change in the physical and chemical properties of any molecule the change in physical and chemical properties of any molecule of any molecule due to the change in position a change in relative position you write down due to the change in relative position relative position of the atoms or groups change in relative position of the atoms or groups attached to it in three dimensional space in three dimensional space ok before going into so detail of all these concepts first of all we will try to understand what is the use of this stereo chemistry we have or stereo isomerism let me give you one example here that is the name of the compound is platine t-l-a-t-i-n platine the formula of this is n-h-3 whole twice and cl-2 right this is platine now the structure of platine is this we will discuss this actually this is we are talking about optical isomerism and all because all these comes under stereo isomerism only so we will discuss this in detail later on but right now I am just giving you the idea of why this is important and why we are studying this see the structure of this compound is this and this is the information I am giving you don't put your brain now into it ok we will discuss this and then you will understand ok now you just keep in mind that the structure of this compound is like this it is a square planar geometry cl and cl this molecule you see this is the platinum is the central molecule and it is attached with two ammonia and two chlorine and here also the same thing we have but the difference in these two structure is what in one structure the first one the two ammonia group is present at 90 degree from each other mutually 90 degree right and here it is at 180 degree correct so now you see when the identical group present at 90 degree from each other then this compound is cis and we call it as cisplatin don't you like think on it that how do we get this what is cis and all what is 90 and 180 just you just you write it down ok if you do not understand this why it is cis and why it is transplatin then we will discuss this ok so you don't panic now just you understand when the NH3 is present at diagonally opposite to each other it is trans and when it is at 90 degree from each other it is cis ok so this is basically the two isomers of this compound we have platinum right it exist in two different form one is cisplatin other one is transplatin now what is the difference in these two structure we have the only difference is the relative position of these molecules right NH3 and Cl right the relative position of these molecules ok so in this the relative position is different so what happens with this the property of the molecule changes and which is nothing but the isomers we have when you change the molecule relative position of the molecule in three dimensional space the property of the molecule also changes and this property changes to a to an extent through which one of this form yes cis and trans ok so we are not going into diapole moment and all ok so one of this form you see here this question they have asked many times in neat exam also this cisplatin is used in cancer therapy cancer therapy as a drug cancer drug we also call it as but this is not at all useful for cancer therapy so the point I am trying to make here it is what the molecular formula is same for both the compound what we are changing we are only changing the relative position of these molecules right here it is at 90 degree here it is at 180 degree and with change in this relative position the property of the molecule changes to such an extent so that one form is useful in cancer therapy and other form is not useful right so that is how the importance of stereochemistry we have this all this is study of properties of this molecule we do under under so that is why all this pharmaceutical industry we have they have they have all these phd scholar in chemistry organic chemistry and all ok so the point here is what that just we are changing the relative position of this molecule and one form is applicable or one form is useful for cancer therapy other form is not so you can understand till what extent the properties of the molecule changes that's why in all these pharmaceutical industries that we have whenever they are going to produce a drug or new drug or medicine first of all they study the stereo aspect of that particular drug right stereo aspect means what stereo study means what the relative position of the molecule when changes how the property of the molecule changes understood so the point here is what all these things we do under this stereo isomerism difference is stereo structural what we have in structural we have the connectivity is different but here the relative position in three dimensional space is different right now the first thing this is what the importance of this particular topic we have in our life ok and the first thing we are going to understand here our first type of isomerism we are going to see that is geometrical isomerism geometrical isomerism ok now one thing you tell me if I write down two structure here one is suppose C double bond C and here we have suppose anything chlorine hydrogen and this side we have hydrogen and chlorine this one and C double bond C we have hydrogen chlorine hydrogen chlorine first of all these two compounds are same or different that you answer me and one more example I will write down this one these two so these two compounds are same or different these two compounds are same or different tell me that yeah this we are doing under isomerism correct first two these two are same or different or these two are same or different first is different second is same first one is different ok see why these first two compounds are different because here the free rotation is hindered here because of the pi bond here ok how this pi bond forms this carbon carbon as sigma bond and this p orbital when overlaps laterally right this kind of overlap forms pi bond and if this rotation is hindered because we cannot rotate this particular carbon by along this axis like this we cannot rotate if you rotate this bond will break right and we cannot break the molecule here right so here what happens what we say whenever double bond is present so the free rotation is hindered or free rotation is not possible not possible or hindered and in these two since you have sigma bond so we can easily rotate this and we will get this suppose this carbon if you rotate like this like this if you rotate the hydrogen will come here chlorine will go down and we will get this these two compounds are actually the same compound we have but these two compounds are different different in the same squad when you try to find out the dipole moment stability and all ok you will have you will get different stability of these two compounds and different dipole moment also see what I said this pi bond if suppose this pi bond is not there only single bond is there carbon carbon single bond right so one of these carbon we can rotate along this axis like this we can rotate since there is only one bond is present here but this kind of rotation this kind of rotation is not possible when we have pi bond present but in this case if you try to rotate this molecule along this then obviously this bond you have to break this pi bond this pi bond you have to break right so in whenever you have pi bond present then this kind of free rotation is not possible and we say the free rotation is hindered over there and when the free rotation is hindered right when the free rotation is hindered so this from this molecule we cannot get this molecule the entire molecule we can flip but we cannot flip one particular carbon any of these carbon we cannot flip because of the double bond but here what happens we have only one bond present here like this so this carbon you can easily rotate along this line like this one rotation you do 180 degree or by some angle this chlorine will come here hydrogen will come here so with this rotation you will get this compound only which is there in the top right so that's why these two compounds are similar compound and these two compounds are different compound okay so geometrical isomerism is possible when we have this kind of arrangement okay there are other possibility also like when we have ring and double bond within the ring so basically geometrical isomerism possible because of double bond first case because of ring second case and because of double bond inside the ring double bond inside the ring okay in these three cases geometrical isomerism is possible right now in this we also since these two compounds are different like we said these two compounds are different now what is the name of this compound you will write IOPC name of this will be what what is the IOPC name of this compound this one what is the IOPC name of this one one to dichloroethene one to dichloroethene so this one is one to dichloroethene इस अथ आँ न exciting what about this one.. अदिचार न said is it also one comma two �落 अ रहा scripture iron यहसРИoned वोट उतबन आँapat औथ औट अ गधउर डअन इस रही आदीन करše नोंaste both compound a are ones and two वोट नेम जब ट़ाँत कर सद आजर नों the name itself is only one, of one, according to वोट उतभ़ करे आप तीओताicit justamente the properties and these two molecules are different in nature these two molecules having different nature but according to IOPSC the name of both compound is 1, 2, diaclodoethane now when you go reverse of this and if I ask you draw the structure of 1, 2, diaclodoethane then you will draw either this one some of you will draw this one some of you will draw this one but since both compounds are different so how do you know that we are talking about which compound here we have the problem in IOPSC right IOPSC given us this rule and according to this rule the name of both compound is 1, 2, diaclodoethane so how do we differentiate this that whether we are talking about this compound or this compound that's the question now so for that we are using two different term here and that term is cis and trans cis and trans ENZ is different in different case ENZ we use ENZ we use when we have we'll discuss when we use ENZ we have cis and trans we have ENZ we have sin and anti also okay so that you let it be you don't go there now we will stop here only okay we don't have that much time okay now next class we'll try to understand how to find out whether geometrical isomerism is possible or not and when do we write down cis and when do we write down trans for a given compound understood so let me give you one thing this particular example is cis form and this one is trans form so when I write down the name of this compound I'll write cis 1, 2, diaclodoethane and for this we'll write trans 1, 2, diaclodoethane so when you use this cis and trans term you will actually understand that whether this chlorine the position of chlorine is what we cannot discuss this advetma we don't have that much time okay when we use cis and trans term we will discuss this in the next class yeah we will finish nomenclature and if time permits we will continue with this tomorrow okay so we'll stop here only okay thank you