Welcome back students so since we have learned quite a lot about the phenomenon of resonance now this will be the last module we will learn the application of resonance and proceed to the next electronic effect that is the introduction of hyper Conjugation alright so when you talk about the application of a resonance is basically the phenomena which helps us to understand the stability in the compound so here we are going to learn the acid strength  of carboxylic acid as we know the fact any components acid if its conjugate base is stable so let’s look at the structure of carboxylic acid and if it donates a proton it forms a conjugate base which is called as a carboxylate ion as we have seen early well as now we’re having 2 structure one is a carboxylic acid and others carboxylate ion we will try and draw the resulting structure of both of this because both of them are having a loan ordered by condition present then which is one of the condition which makes the compound eligible to show phenomenal resonance so look at the carboxylic acid structure the one visit to the left if we should delocalization over here we’ll get a resonating structure which can be simply drawn like this so since the lone pair from the oxygen atom as delocalized it is experiencing loss of a lone pair so we carry a positive charge and the double bonded oxygen gaining  one additional electron pair so caring and negative charge which means now this newly opting resonating structure carries a positive and the negative charge which means this structure is the charge separated Structure now try to work on the phenomenal for resonance in this structure right here which is nothing but the carboxilate  ion so we again have a loan alternate by condition present over here so if we sure do localization will get one more Resorting  structure which is equivalent of this carboxylic ion and you can see that there’s only negative charge which is getting dispersed delocalized so i will say that in this structure 1and 2 which are the equal and structure you will find that this equal and structures are charged the localized structure and whenever you get a chance temperature structure it is relatively  a less stable structure on the other hand charge delocalized which means if only one charge is getting dispersed  the locals or several items then that delocalize a structure is always a most stable structure than the other and now you think about why are we calling this application we see that any compound acid if its conjugate base is stable so in case of carboxylic acid we saw that the conjugate base was a carboxylate ion which is giving us charge delocalized structure which is more stable more stable the conjugate bases more stable is the acid from which their conjugate bases obtained so likewise student  and if you try and work on this sell phonic acid or if you try and work on the phenol you will find that the charge delocalized structures are going to be more stable due to phenomenal for resonance so phenomenal resonance can simply justify the acid strength of the Compounds well having known this now we are going to learn or see a simple sequence of acid strength but the most important one so remember if you talk about the several acid the sell phonic acid it is the strongest among all because is reasoning  structures are more stable and after so sulphuric acid  in the next acid is their logs leak acid followed by we have a carboxylic  acid and then we have phenol by   after phenol all the structure of the compound  which comes most acid is methanol  check out here we have a methanol  all then relatively weaker acid is a water and then we again have any other alcohol student please look at this methanol is the only exceptional alcohol which is more acid than  water and rest alcohols are weaker acid than water and after this we have alkynes then we have ammonia and then we get alkenes followed by alkenes so this is a simple order of acid strength of several compound  and you got to remember this all right students now having said that we are going to learn application of resonance and this is what was the application of a resonance now we’ll see introduction to the phenomena of a hyper conjugation and  there are several more news coming up right there will justify each one of this name but for the timing let’s look at this reaction so we have tertiary butyl halide  highlight when this tertiary butyl and is brought in presence of a polar solvent like water again we learn what it means a polar then the six bond here to literally breaks and which means the bond pair between can have been completely taken by X so the carbon has lost born pair and therefore produces a positively charged species like this positively charged species were positive charge is carried  bicarbonate Called as  carbo cation now let’s take that carbon cation over here and remove all this methyl  group will get the structure like this so this is a general representation of carbo cation  and let’s take a replicate  that so we are taken 4 such general representation of a carbo cation a time and now instruction number one right there we are fulfilling all the valances  let’s see by methyl groups so now that carbo cationic which is carrying  a positive charge is attached to three more carbon so the nature of the carbon carrying  positive charge is Tertiary  we call it a Tertiary  carbo cation same way if we take 2 methyl  group  to such carbon you will call it as the secondary carbo cation since it is attached 2 the carbon  when so if you move further if I’m fulfilling to valances with edges and one with methyl the nature of carbonic  cation  is primary and if I fulfill all the valances  with edges I will call it as the methyl carbo cation since it looks like methyl  so the nature of carbon carrying  positive charge decides the nature of carbon cation and it is said that among all this the order of stability is found to be Tertiary  the most then secondary then primary and methyl is stable carbo cation  and why is the order so can be proven by the phenomenon of hyper conjugation so in the very next model will try and prove this order and with respect to this we will learn the phenomenal hyper conjugation but we’ll stop here in this module thank you